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SUMMARY:poster popups
DTSTART;VALUE=DATE-TIME:20230509T132500Z
DTEND;VALUE=DATE-TIME:20230509T134500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-414@meetings.aip.de
DESCRIPTION:Speakers: Arooj Faryad ()\, Fallon Konow (Georgia State Univer
 sity / University of Rome Sapienza  / University of Rome Tor Vergata / Nat
 ional Institute of Astrophysics (INAF))\, José Roberto Canivete Cuissa (I
 RSOL)\, Matteo Cantoresi (University of Rome Tor Vergata)\, Meetu Verma ( 
 Leibniz-Institut für Astrophysik Potsdam (AIP))\, Nikolina Milanović (Ma
 x Planck Institute for Solar System Research)\, Philip Lindner (Leibniz-In
 stitut fuer Sonnenphysik (KIS))\nFallon Konow	- A New Instrument for Synop
 tic Space Weather Observations	\nMeetu Verma- Tales of Two Pores – Obser
 ved with GREGOR IFU and HiFI\nJosé Roberto Canivete Cuissa - Vortices and
  Alfvénic pulses in the simulated solar atmosphere			\nArooj Faryad - Aut
 omatic detection of Ellerman bombs in Halpha using COCOPLOTs	\nNikolina Mi
 lanović - Thermal structuring and evolution of coronal bright points	\nMa
 tteo Cantoresi  - Scaling properties of Coronal Holes photospheric magneti
 c fields\nPhilip Lindner - Decay of a photospheric transient filament at t
 he boundary of a pore and the chromospheric response\n\nhttps://meetings.a
 ip.de/event/24/contributions/414/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/414/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Magnetic field changes in the photosphere during solar flares and 
 their association with flare ribbons
DTSTART;VALUE=DATE-TIME:20230509T155500Z
DTEND;VALUE=DATE-TIME:20230509T161000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-315@meetings.aip.de
DESCRIPTION:Speakers: Rahul Yadav (University of Colorado\, Boulder)\nAbru
 pt and permanent photospheric magnetic field changes have been observed in
  many flares. It is believed that such changes are related to the reconfig
 uration of magnetic field lines\, however\, the real origin is still uncle
 ar. I will present the analysis of 37 flares observed by the Solar Dynamic
 s Observatory (SDO). The characteristics of the magnetic field changes in 
 the flare events are determined using HMI high-cadence vector magnetogram 
 (135 s)\, whereas the ribbon properties are derived from co-aligned AIA 16
 00 Å images. We find that pixels swept up by ribbons do not always exhibi
 t permanent changes in the field. However\, when they do\, ribbon emission
  typically occurs several minutes before the start of field changes. The c
 hanges in the properties of the field show no relation to the size of acti
 ve regions but are strongly related to the flare-ribbon properties. We fin
 d that the duration of permanent changes in the field is strongly coupled 
 with the duration of the flare. Our results suggest that changes in photos
 pheric magnetic fields are caused by a combination of two scenarios: contr
 action of flare loops driven by magnetic reconnection and coronal implosio
 n.\n\nhttps://meetings.aip.de/event/24/contributions/315/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/315/
END:VEVENT
BEGIN:VEVENT
SUMMARY:On diversity of spectral shapes of hydrogen Lyman lines and Mg II 
 lines in a quiescent prominences
DTSTART;VALUE=DATE-TIME:20230509T154000Z
DTEND;VALUE=DATE-TIME:20230509T155500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-306@meetings.aip.de
DESCRIPTION:Speakers: Pavol Schwartz (Astronomical Institute\, Slovak Acad
 emy of Sciences)\nA quiescent prominence was observed on October 22\, 2013
  quasi-simultaneously and nearly co-spatially in the Lyman series of hydro
 gen by SoHO/SUMER and in the Mg II h&k lines by IRIS. Such spectroscopic o
 bservations comprising multiple lines offer an excellent opportunity for d
 iagnostics of prominence plasma and the dynamics of its fine structures. H
 owever\, it also invokes significant challenges when compared with synthet
 ic spectra provided by radiative transfer modelling. Only a few similar co
 ordinated datasets of Lyman and Mg II h&k observations were ever obtained 
 in prominences. We present here the first spectroscopic analysis of this u
 nique dataset. Moreover\, for the first time\, we assess the influence of 
 noise on the statistics of profile characteristics. We focus on the follow
 ing characteristics – the number of distinct peaks\, integrated line int
 ensity\, center-to-peak ratio describing the depth of the reversal of two-
 peaked profiles\, and the asymmetry of peaks. There occur many profiles of
  both Lyman and Mg II lines which except of two major peaks\, contain also
  lower peaks – hereafter called as minor peaks. Nature of these\, possib
 ly spurious minor peaks is uncertain. They may be either due to noise or v
 igorous dynamics of the prominence. We show that noise has a negligible ef
 fect on the integrated intensities of all lines but it significantly affec
 ts the classification of spectral profiles using the number of distinct pe
 aks\, the reversal depth and also the peak asymmetry. We also demonstrate 
 that by taking into account an influence of noise\, we can assess which ch
 aracteristics of particular lines are suitable for diagnostics of differen
 t properties of prominence. For example\, we show that the minor peaks of 
 the Lyman line profiles are mostly caused by noise\, which means that only
  the dominant peaks should be used for statistical analyses or comparisons
  with synthetic spectra. On the other hand\, for Mg II k&h\, distinction b
 etween multi-peaked profiles with low peaks and profiles with deep reversa
 ls lies mainly in the dynamics of multiple fine structures located along a
  line of sight. The complex\, multi-peaked profiles are observed in places
  where multiple fine structures with different line-of-sight velocities ar
 e crossing the line of sight while the profiles with deep reversals likely
  correspond to instances when we observe single fine structure or multiple
  fine structures but with similar line-of-sight velocities. Such results l
 ead to a conclusion that if we are interested in the diagnostics of dynami
 cs of prominence fine structures\, the best approach is to use a combinati
 on of profile asymmetry in the Lyman lines together with the complex profi
 les of Mg II h&k lines. On the other hand\, if we want to diagnose the tem
 perature and pressure of individual prominence fine structures\, we need t
 o focus on deeply reversed Mg II h&k line profiles in combination with the
  Lyman lines and to analyse the depth of central reversal and the integrat
 ed intensity.\n\nhttps://meetings.aip.de/event/24/contributions/306/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/306/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Plasma thermalisation from wave damping seen in super-penumbral fi
 brils
DTSTART;VALUE=DATE-TIME:20230509T152500Z
DTEND;VALUE=DATE-TIME:20230509T154000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-310@meetings.aip.de
DESCRIPTION:Speakers: William Bate (Queen's University Belfast)\nThe Inter
 ferometric Bidimensional Spectrometer (IBIS) at the Dunn Solar Telescope (
 DST) was employed to capture high spatial resolution spectral scans of a s
 unspot in the H-alpha line. These scans allowed for the examination of sup
 er-penumbral fibrils\, including their transverse motions both parallel an
 d perpendicular to the line of sight. Near ubiquitous transverse oscillati
 ons of the fibrils have been observed and statistics gathered on their pro
 perties\, which are consistent with previous investigations. Further exami
 nation of cases demonstrating well-resolved fibril oscillations were perfo
 rmed\, which allowed us to track their propagation velocities and associat
 ed energy flux along the length of the fibril. Additionally\, analysis of 
 the H-alpha line width has been performed\, which is known to correlate wi
 th plasma temperature. This allowed for a unique investigation of whether 
 the energy damped from the transverse fibril oscillations provides evidenc
 e of thermalisation of the local plasma. Here\, I will report on the energ
 y damping and associated fluctuations in the H-alpha line width\, which we
  believe is evidence of MHD wave dissipation in the form of plasma thermal
 isation.\n\nhttps://meetings.aip.de/event/24/contributions/310/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/310/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Evidence of external reconnection between an erupting mini-filamen
 t and ambient loops observed by Solar Orbiter/EUI
DTSTART;VALUE=DATE-TIME:20230509T151000Z
DTEND;VALUE=DATE-TIME:20230509T152500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-320@meetings.aip.de
DESCRIPTION:Speakers: Zhuofei Li (MPS)\nMini-filament eruptions are one of
  the most common small-scale transients in the solar atmosphere. They are 
 small-scale analogs to solar filaments. They are associated with coronal j
 ets that represent transient\, collimated plasma ejections along open fiel
 ds or far-reaching coronal loops. One particular type is blowout jets. The
 se often come along with erupting loops or twisted filaments at the base o
 f the jets. Consequently they have a more dynamic base and also often a wi
 der spire than standart jets. Recently\, a mini-filament eruption model ha
 s been put forward\, in which a successful mini-filament eruption drives a
  blowout jet\, while a partial or failed mini-filament eruption causes a s
 tandard jet. During blowout jets\, many blobs have been observed and drawn
  much attention as they could provide evidence of the magnetic reconnectio
 n process\, because these blobs are odten identified with plasmaoids in th
 e current sheet. However\, it is still difficult to observationally clarif
 y the relation between the moving plasma blobs and magnetic reconnection. 
 The clarification is mainly limited by the low spatio-temporal resolution 
 of previous data. Here\, with a combination of 174 Å images at high spati
 al resolution and high cadence taken by the Extreme Ultraviolet Imager on 
 board Solar Orbiter and images of the Atmospheric Imaging Assembly on boar
 d Solar Dynamics Observatory\, we investigate in detail an erupting mini-f
 ilament over a weak magnetic field region on 2022 March 4. During the erup
 tion\, two bright ribbons clearly appeared underneath the erupting mini-fi
 lament as it quickly ascended. Subsequently\, some dark materials blew out
  when the erupting mini-filament interacted with the outer ambient loops\,
  thus forming a blowout jet characterized by a widening spire. At the same
  time\, a chain of small bright blobs with diameters of 1–2 Mm are inter
 mittently expelled from the interaction region between the erupting mini-f
 ilament and ambient loops and propagated along the post-eruption loops tow
 ard the footpoints of the erupting fluxes at a speed of ~ 100 km/s. They h
 ave short lifetimes\, varying from 30 s to 90 s. They also caused a semi-c
 ircular brightening structure. We suggest that these fast-moving blobs are
  evidence for magnetic reconnection. We performed a differential emission 
 measure (DEM) analysis and found that various brightenings show plasma tha
 t is heated during the mini-filament eruption\, e.g. two bright ribbons\, 
 footpoints of the ambient loops\, and the interaction region. Based on the
  features aforementioned\, we suggest that the mini-filament eruption firs
 t experiences internal reconnection that occurs underneath the erupting mi
 ni-filament and then external reconnection between the mini-filament and t
 he ambient loops. The transfer of mass and magnetic flux from the erupting
  mini-filament to the ambient corona is mainly due to the external reconne
 ction.\n\nhttps://meetings.aip.de/event/24/contributions/320/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/320/
END:VEVENT
BEGIN:VEVENT
SUMMARY:On the stability of large magnetic solar structures
DTSTART;VALUE=DATE-TIME:20230509T145500Z
DTEND;VALUE=DATE-TIME:20230509T151000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-321@meetings.aip.de
DESCRIPTION:Speakers: Jan Jurcak (Astronomical Institute of the CAS)\nWe w
 ill review the recent observational results that show the key role played 
 by the vertical component of the magnetic field (B$_\\mathrm{ver}$) in the
  inhibition of convection in the solar photosphere. In sunspots\, only reg
 ions with B$_\\mathrm{ver}$ stronger than a critical value of approximatel
 y 1.8 kG (the critical value is dependent on the data used\, definition of
  the umbral boundary\, inversion scheme\, etc.) are stable against convect
 ion and the intensity boundaries of stable umbrae can be equally outlined 
 by this critical B$_\\mathrm{ver}$. In regions with B$_\\mathrm{ver}$ weak
 er than the critical value\, more vigorous modes of magneto-convection tak
 e over. This behavior is observed during the formation of penumbra and lig
 ht bridges and during the decay of sunspots and pores. We will compare the
 se observations to analyses of sunspots simulations and to theoretical mod
 els describing the stability of overturning convection in the presence of 
 magnetic fields and we will discuss the repercussion in the life cycle of 
 magnetic structures.\n\nhttps://meetings.aip.de/event/24/contributions/321
 /
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/321/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sunspot penumbral evolution: a puzzle under construction
DTSTART;VALUE=DATE-TIME:20230509T143000Z
DTEND;VALUE=DATE-TIME:20230509T145500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-358@meetings.aip.de
DESCRIPTION:Speakers: Mariarita Murabito (INAF OACN)\nThe penumbra is an i
 ntriguing part of a sunspot where the coupling between magnetic field and 
 plasma is characterized by peculiar physical conditions. Although it has b
 een the focus of many observational and theoretical studies\, the processe
 s involved in the formation and decay of a sunspot penumbra are still not 
 fully understood. I will give a brief summary of recent observations leadi
 ng valuable contributions to better understanding these processes.\n\nhttp
 s://meetings.aip.de/event/24/contributions/358/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/358/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Insights Into Confined/Eruptive Stellar Flare Nature using Compreh
 ensive Statistical Analysis of Magnetic and Thermodynamic Properties of So
 lar Flares Observations
DTSTART;VALUE=DATE-TIME:20230509T103000Z
DTEND;VALUE=DATE-TIME:20230509T104500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-308@meetings.aip.de
DESCRIPTION:Speakers: Maria Kazachenko (University of Colorado - Boulder /
  National Solar Observatory)\nSolar flares sometimes lead to coronal mass 
 ejections that directly affect the Earth's environment. However\, a large 
 fraction of flares\, especially on solar-type stars\, are confined flares.
  What are the differences in physical properties between confined and erup
 tive flares?  For the first time\, we quantify thermodynamic and magnetic 
 properties of hundreds confined and eruptive flares of GOES class C5.0 and
  above\, 480 flares total. We first analyze large flares of GOES class M1.
 0 and above observed by the SDO\, 216 flares total\, including 103 eruptiv
 e and 113 confined flares\, from 2010 until 2016 April\; we then look at t
 he entire dataset above C5.0 of 480 flares. We compare GOES X-ray thermody
 namic flare properties\, including peak temperature and emission measure\,
  and active-region and flare-ribbon magnetic field properties\, including 
 reconnected magnetic fluxes and peak reconnection rates. We find that conf
 ined and eruptive flares have similar distributions of reconnection flux. 
 Confined flares\, however\, have larger peak magnetic reconnection rates\,
  are more compact\, and occur in larger active regions than eruptive flare
 s. These findings suggest that confined flares are caused by reconnection 
 within more compact\, stronger\, lower lying magnetic-field regions in lar
 ger ARs that reorganizes smaller fractions of ARs. This reconnection proce
 eds at faster rates and ends earlier\, leading potentially to more efficie
 nt flare particle acceleration in confined flares.\n\nhttps://meetings.aip
 .de/event/24/contributions/308/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/308/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Detection of the Evershed flow by the application of the SOM techn
 ique
DTSTART;VALUE=DATE-TIME:20230509T101500Z
DTEND;VALUE=DATE-TIME:20230509T103000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-314@meetings.aip.de
DESCRIPTION:Speakers: Paolo Romano (INAF - Catania Astrophysical Observato
 ry)\nWe present the results obtained from applying the Self Organizing Map
  technique to a spectral dataset of monochromatic images acquired by the I
 nterferometric Bidimensional Spectropolarimeter at the Dunn Solar Telescop
 e\, along the Ca II 854.2 nm and Hα 656.28 nm lines. This technique allow
 ed us to segment the photospheric and chromospheric penumbra fine structur
 e\, revealing the presence of the Evershed flow in the chromosphere along 
 the portions of the penumbral filaments near the umbra. In addition\, the 
 flow velocity as a function of distance from the spot center in the periph
 eral regions of the super-penumbra was consistent with the inverse-Evershe
 d flow. These signatures\, along with slight differences in the chromosphe
 ric plasma velocities measured along the two spectral lines\, provided us 
 with the opportunity to combine the Evershed and inverse-Evershed flows in
  the same context\, in accordance with the uncombed model of the sunspot p
 enumbra.\n\nhttps://meetings.aip.de/event/24/contributions/314/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/314/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sausage wave modes in small magnetic pores observed with Solar Orb
 iter/PHI
DTSTART;VALUE=DATE-TIME:20230509T100000Z
DTEND;VALUE=DATE-TIME:20230509T101500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-305@meetings.aip.de
DESCRIPTION:Speakers: Shahin Jafarzadeh (Max Planck Institute for Solar Sy
 stem Research\, Germany))\nWe have exploited seeing-free and high-quality 
 observations of several small magnetic pores from the High Resolution Tele
 scope (HRT) of the Polarimetric and Helioseismic Imager (PHI) on board the
  Solar Orbiter spacecraft\, during its first close perihelion in March 202
 2 (at a distance of 0.5 au from the Sun). Only such small magnetic pores\,
  captured at stable observing conditions\, could manifest (large) area flu
 ctuations\, on the order of 30% variations\, that is an indication of (non
 -linear) fast sausage (surface) modes. Furthermore\, cross correlations be
 tween perturbations in intensity\, area\, line-of-sight velocity\, and mag
 netic fields have provided us with additional wave signatures\, that toget
 her with applications of modern analysis techniques\, such as the Spectral
  Proper Orthogonal Decomposition (SPOD)\, we have been able to characteris
 e the underlying MHD wave modes in more details.\n\nhttps://meetings.aip.d
 e/event/24/contributions/305/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/305/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Scrutinising nature of magnetic and flow fields in complex active 
 region with HiFI+ and GRIS
DTSTART;VALUE=DATE-TIME:20230509T094500Z
DTEND;VALUE=DATE-TIME:20230509T100000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-297@meetings.aip.de
DESCRIPTION:Speakers: Robert Kamlah (Leibniz-Institut fuer Astrophysik Pot
 sdam (AIP))\nThis study investigates the photospheric and chromospheric fl
 ow field in active region NOAA 13096\, which consists of pores\, sunspots 
 with partial penumbrae\, and light bridges. The improved High-resolution F
 ast Imager (HiFI+) and GREGOR Infrared Spectrograph (GRIS) acquired high-r
 esolution data at the 1.5-meter GREGOR solar telescope at Observatorio del
  Teide\, Izaña\, Tenerife\, Spain. The Helioseismic and Magnetic Imager (
 HMI) onboard the Solar Dynamics Observatory (SDO) complements the GREGOR d
 ata with synoptic full-disk continuum images and line-of-sight (LOS) magne
 tograms. Background-Subtracted Activity Maps (BaSAMs) were used to locate 
 areas with enhanced activity\, for which Local Correlation Tracking (LCT) 
 provides horizontal proper motions and GRIS LOS velocities and full-Stokes
  polarimetry. We present first results of the three-dimensional photospher
 ic and chromospheric flow and magnetic fields scrutinizing the (inverse) E
 vershed effect in a complex active region.\n\nhttps://meetings.aip.de/even
 t/24/contributions/297/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/297/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Active region evolution
DTSTART;VALUE=DATE-TIME:20230509T091500Z
DTEND;VALUE=DATE-TIME:20230509T094500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-408@meetings.aip.de
DESCRIPTION:Speakers: Lucie Green (MSSL)\nhttps://meetings.aip.de/event/24
 /contributions/408/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/408/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The role of the chromospheric canopy in the formation of a penumbr
 a
DTSTART;VALUE=DATE-TIME:20230509T131000Z
DTEND;VALUE=DATE-TIME:20230509T132500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-312@meetings.aip.de
DESCRIPTION:Speakers: Philip Lindner (Leibniz-Institut fuer Sonnenphysik (
 KIS))\nWhile it is being conjectured that a chromospheric canopy plays a r
 ole in penumbra formation\, it has been difficult to find observational ev
 idence of the connectivity between the photosphere and the chromosphere. \
 n\nWe investigate the existence of a chromospheric canopy as a necessary c
 ondition for the formation of a penumbra and aim to find the origin of the
  inclined magnetic fields. Spectropolarimetric observations of NOAA AR 127
 76 from the GRIS@GREGOR instrument were analyzed. Atmospheric parameters w
 ere obtained from the deep photospheric Ca I 10839 Å line (VFISV inversio
 n code)\, the mostly photospheric Si I 10827 Å line (SIR inversion code) 
 and the chromospheric He I 10830 Å triplet (HAZEL inversion code). \n\nIn
  the deepest atmospheric layers\, we find that the magnetic properties (in
 clination and field strength distribution) measured on the sunspot sector 
 with fully fledged penumbra are similar to those measured on the sector wi
 thout penumbra. Yet\, in higher layers\, magnetic properties are different
 . In the region showing no penumbra\, almost vertical chromospheric magnet
 ic fields are observed. Additionally\, thin filamentary structures with a 
 maximum width of 0.1 arcsec are seen in photospheric high-resolution TiO-b
 and images in this region. \n\nThe existence of a penumbra is found to be 
 discriminated by the conditions in the chromosphere. This indicates that a
  chromospheric canopy is a necessary condition for the formation of a penu
 mbra. However\, our results demonstrate that inclined fields in the chromo
 spheric canopy are not needed for the development of inclined fields in th
 e photosphere. We question the `fallen-magnetic-flux-tubes' penumbra forma
 tion scenario and favor a scenario\, in which inclined fields emerge from 
 below the surface and are blocked by the overlying chromospheric canopy.\n
 \nhttps://meetings.aip.de/event/24/contributions/312/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/312/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Active region evolution – Tracking active regions from the near-
 Earth side to the solar far side (and back)
DTSTART;VALUE=DATE-TIME:20230509T125500Z
DTEND;VALUE=DATE-TIME:20230509T131000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-313@meetings.aip.de
DESCRIPTION:Speakers: Hanna Strecker (Instituto de Astrofísica de Andaluc
 ía ((IAA-CSIC) & Spanish Space Solar Physics Consortium)\nFor a long time
 \, the study of the evolution of active regions in the solar photosphere h
 as been limited by the transit time of the active regions over the solar d
 isk as seen from Earth. Since its launch in February 2020\, ESA/NASA's Sol
 ar Orbiter spacecraft provides us\, from time to time\, with the possibili
 ty to see the solar far side. The Polarimetric and Helioseismic Imager (SO
 /PHI)\, one of its ten instruments\, delivers data of the solar photospher
 e in intensity and vector magnetic field. In February 2021\, during Solar 
 Orbiter’s first superior conjunction\, the full disk telescope of SO/PHI
  acquired the first polarimetric data of the photospheric solar far side. 
 We combine this data with data from the Helioseismic and Magnetic Imager (
 HMI) flying on board NASA’s Solar Dynamic Observatory. This enables an a
 lmost 360º view of the Sun and allows\, for the first time\, the tracking
  of active regions over a full solar rotation almost without interruption\
 , from the near-Earth side to the far side. We study the evolution of four
  active regions in intensity and LOS magnetograms while they rotate from t
 he near-Earth side\, seen by HMI\, to the solar far side\, into the field-
 of-view (FOV) seen by SO/PHI. Three of the active regions decay on the sol
 ar far side and do not show any signal in intensity when reaching the FOV 
 of SO/PHI. One active region crosses the disk as seen from Earth while app
 earing to decay. However\, new flux emerges on the solar far side leading 
 to the development of pores and a small sunspot before the region reaches 
 the limb as seen in SO/PHI and reappears on the near-Earth side. We will p
 resent the longest almost uninterrupted study of the evolution of the magn
 etic field of active regions\, achieved so far. This demonstrates the uniq
 ueness of combining Solar Orbiter and near-Earth side observations to cont
 inuously study the evolution of active regions from their emergence to the
 ir decay.\n\nhttps://meetings.aip.de/event/24/contributions/313/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/313/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantifying Systematic Biases in the Measurements of the Open Magn
 etic Flux
DTSTART;VALUE=DATE-TIME:20230509T124000Z
DTEND;VALUE=DATE-TIME:20230509T125500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-307@meetings.aip.de
DESCRIPTION:Speakers: Ivan Milic (Leibniz Institute for Solar Physics (KIS
 ))\nOpen magnetic flux in the photosphere\, especially at the poles\, pres
 ents an important boundary condition for modeling the heliospheric field. 
 The field extrapolated from polar observations is roughly 50% lower than t
 he in-situ measurements (“open flux problem”). Here we present our eff
 orts to characterize biases in the open flux inference and that way explai
 n the discrepancy above. We use a state-of-the-art plage-like MURaM MHD si
 mulation of the solar photosphere to model polarized spectra of magnetical
 ly sensitive Fe I 630 nm doublet lines\, observed by the Hinode SOT/SP ins
 trument. We mimic the realistic observation at the disk center and the pol
 e by calculating emergent intensity\, applying instrumental effects  (spat
 ial and spectral PSF\, binning)\, and adding the photon noise. We then app
 ly different inversion codes built upon different physical assumptions to 
 these synthetic observations and compare results to the original simulatio
 n.\n\nAt the disk center\, a significant fraction (20\, down to 50%) of op
 en flux gets lost for the telescopes with apertures smaller than 1m. At th
 e pole\, the magnetic field disambiguation becomes a critical part: the as
 sumption of the radial field underestimates flux by around 30% while the i
 nclusion of the telescope PSF further exacerbates the problem. The more in
 -depth investigation that accounts for stray light still yields significan
 t discrepancies between the original and inferred intrinsic properties of 
 the magnetic field. These systematic errors in field diagnostics may be re
 duced by high-resolution or out-of-ecliptic observations.\n\nhttps://meeti
 ngs.aip.de/event/24/contributions/307/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/307/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stereoscopic disambiguation of vector magnetograms: first applicat
 ions to HRT data
DTSTART;VALUE=DATE-TIME:20230509T122500Z
DTEND;VALUE=DATE-TIME:20230509T124000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-304@meetings.aip.de
DESCRIPTION:Speakers: Gherardo Valori (MPS - Max Planck Institute for Sola
 r System Research)\nSpectropolarimetric reconstructions of the photospheri
 c vector magnetic field are intrinsically limited by the 180-degree-ambigu
 ity in the orientation of the transverse component.  So far\, the removal 
 of such an ambiguity has required assumptions about the properties of the 
 photospheric field\, which makes disambiguation methods model-dependent.\n
 \nThe successful launch and operation of Solar Orbiter have made the remov
 al of the 180-ambiguity possible solely using observations of the same loc
 ation on the Sun obtained from two different vantage points. To that purpo
 se\, the Stereoscopic Disambiguation Method was recently developed and suc
 cessfully tested on numerical simulations.\n\nHere we present the first ap
 plication of the SDM to data obtained by the High Resolution Telescope (HR
 T) onboard Solar Orbiter during the March 2022 campaign\, when the angle w
 ith Earth was 27 degrees. The method is successfully applied to remove the
  ambiguity in the transverse component of the HRT vector magnetogram solel
 y using observations (from HRT and from the Helioseismic and Magnetic Imag
 er-HMI)\, for the first time.\n\nThe SDM is proven to provide observation-
 only disambiguated vector magnetograms that are spatially homogeneous and 
 consistent.\nWhile we present here an application combining PHI with HMI d
 ata\, the same method can be applied to magnetic information from Solar Or
 biter together with any Earth-bound observatory.\n\nhttps://meetings.aip.d
 e/event/24/contributions/304/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/304/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Modeling of the solar chromosphere
DTSTART;VALUE=DATE-TIME:20230509T120000Z
DTEND;VALUE=DATE-TIME:20230509T122500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-357@meetings.aip.de
DESCRIPTION:Speakers: Sanja Danilovic (Sanja)\nThe chromosphere is a dynam
 ic and complex layer where all the relevant physical processes happen on v
 ery small spatio-temporal scales. A few spectral lines that can be used as
  chromospheric diagnostics\, give us convoluted information that is hard t
 o interpret without realistic theoretical models. What are the key ingredi
 ents that these models need to contain? In this review\, we present the re
 cent numerical models and how they compare to observations. We will discus
 s the formation and properties of chromospheric structures at different sp
 atial scales and the challenges we meet when modeling the solar chromosphe
 re.\n\nhttps://meetings.aip.de/event/24/contributions/357/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/357/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantifying Poynting Flux in the Quiet Sun Photosphere Using Obser
 vations and Simulations
DTSTART;VALUE=DATE-TIME:20230510T071500Z
DTEND;VALUE=DATE-TIME:20230510T073000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-317@meetings.aip.de
DESCRIPTION:Speakers: Denis Tilipman (University of Colorado\, Boulder\; N
 ational Solar Observatory (NSO))\nThe solar chromosphere and corona are he
 ated by the dissipation of magnetic energy that emerges from the photosphe
 re. The outward flux of magnetic energy\, or Poynting flux\, is therefore 
 important to understand in both qualitative and quantitative terms. It can
  be computed by taking a cross product of electric and magnetic fields\, a
 nd in ideal MHD conditions it can be expressed in terms of magnetic field 
 and plasma velocity. There are existing estimates of Poynting flux in acti
 ve regions and plages\, but the quiet Sun (QS) remains a challenging targe
 t due to resolution effects and polarimetric noise. However\, with upcomin
 g DKIST capabilities\, these estimates will become more feasible than ever
  before.\n\nHere we present our findings from studying QS Poynting flux in
  Sunrise/IMaX observations and MURaM simulations. Since this problem has n
 ot been comprehensively approached before\, and due to the aforementioned 
 challenges of QS observations\, we explore and evaluate multiple methods f
 or computing Poynting flux. For transverse velocities\, we try two inversi
 on methods – a classic correlation tracking approach FLCT and a neural n
 etwork based method DeepVel – and show DeepVel to be the more suitable m
 ethod in the context of small-scale QS flows. Further\, we investigate the
  effect of magnetic field azimuthal ambiguity on Poynting flux estimates\,
  and we describe a new method for azimuth disambiguation. Finally\, we use
  two methods for obtaining the electric field. The first method relies on 
 idealized Ohm's law\, whereas the second is a state-of-the-art inductive e
 lectric field inversion method PDFI\\_SS.\n\nWe compare the resulting Poyn
 ting flux values with theoretical estimates for chromospheric and coronal 
 energy losses and find that some\, but not all\, of Poynting flux estimate
 s are sufficient to match the energy losses. Using MURaM simulations\, we 
 show that photospheric Poynting fluxes vary with optical depth\, and that 
 there is an observational bias that results in underestimated Poynting flu
 xes due to unaccounted shear term contribution.\n\nhttps://meetings.aip.de
 /event/24/contributions/317/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/317/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Center-to-limb variation in Mg II intensities in quiet Sun and act
 ive regions from IRIS
DTSTART;VALUE=DATE-TIME:20230510T070000Z
DTEND;VALUE=DATE-TIME:20230510T071500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-318@meetings.aip.de
DESCRIPTION:Speakers: Megha Anand (nter University Centre for Astronomy an
 d Astrophysics\, Post Bag-4\, Ganeshkhind\, Pune 411007\, India)\nThe sola
 r ultraviolet (UV) and extreme ultraviolet (EUV) radiations which are majo
 r contributors to the solar spectral irradiance (SSI) below 4000 Å\,  sig
 nificantly affect the composition and the thermal structure of the Earth's
  atmosphere. The Magnesium II core-to-wing ratio (also known as the Mg II 
 index) is one of the best proxies for solar activity and UV-SSI variabilit
 y. To date\, the Mg II index has been studied\, assuming Sun-as-a-star usi
 ng low (11 Å) and medium spectral resolution (1 Å) data. On the other ha
 nd\, Mg II h and k line pairs being optically thick\, are highly sensitive
  to the thermodynamical properties of the line-forming region and the view
 ing angle. Therefore\, in this study\, we explore the center-to-limb varia
 tion (CLV) in the Mg II line and continuum intensities in various solar fe
 atures like quiet Sun (QS)\, plage\, inter-plage\, sunspot umbra\, and pen
 umbra using the high spatial and spectral resolution data from the Interfa
 ce Region Imaging Spectrometer (IRIS). Our study indicates that plages wit
 h the lowest magnetic field density show the highest limb darkening as opp
 osed to the QS\, whereas the umbra and penumbra show a combination of both
  limb darkening and brightening depending on their photospheric magnetic f
 ield densities. This would provide us an opportunity to understand the imp
 ortance of the spatially resolved Mg II index on the SSI studies.\n\nhttps
 ://meetings.aip.de/event/24/contributions/318/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/318/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Study of the evolution of magnetic energy and helicity injection i
 n an active region with recurring eruptive events
DTSTART;VALUE=DATE-TIME:20230509T081500Z
DTEND;VALUE=DATE-TIME:20230509T083000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-319@meetings.aip.de
DESCRIPTION:Speakers: Marcelo López Fuentes (Instituto de Astronomía y F
 ísica del Espacio (CONICET-UBA))\nSolar events such as flares and coronal
  mass ejections are the most energetic phenomena affecting interplanetary 
 space in timescales ranging from minutes to a few days. There has been\, i
 n recent years\, a strong interest in characterizing the processes that in
 ject magnetic energy and helicity in solar active regions (ARs) and the me
 chanisms that destabilize their magnetic structure leading to the energy r
 eleased during those events. We analyze the magnetic evolution of AR NOAA 
 11476 that produced a series of minifilament confined eruptions of the “
 surge” type accompanied by M-class flares. In a previous work\, we found
  that these events are associated to the presence of a small rotating bipo
 le that emerged in the middle of the globally bipolar AR magnetic configur
 ation. The bipole rotation preceded and concurred in time with the observe
 d ejections. Magnetic flux cancellation is also identified along the polar
 ity inversion line of the bipole where the minifilaments were recurrently 
 formed and ejected. Here we combine the analysis\, for the full AR and the
  rotating bipole\, of the evolution of a series of magnetic parameters com
 puted from SDO/HMI vector magnetograms with estimations of the magnetic en
 ergy and magnetic helicity injection obtained using the Differential Affin
 e Velocity Estimator for Vector Magnetograms (DAVE4VM) method. This proced
 ure is based on the determination\, from vector magnetograms\, of the affi
 ne velocity field constrained by the induction equation. Our results provi
 de a series of relations between the studied parameters that define proxie
 s of the magnetic evolution of the AR that\, eventually\, can be used as p
 ossible precursors of active events.\n\nhttps://meetings.aip.de/event/24/c
 ontributions/319/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/319/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chromospheric horizontal propagating waves revealed by fast cadenc
 e imaging in Ca II K with DKIST’s Visible Broadband Imager
DTSTART;VALUE=DATE-TIME:20230509T073000Z
DTEND;VALUE=DATE-TIME:20230509T074500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-316@meetings.aip.de
DESCRIPTION:Speakers: Catherine Fischer (National Solar Observatory)\nThe 
 Daniel K. Inouye Solar Telescope is currently acquiring first science data
  as part of its Operations Commissioning Phase. High-resolution\, fast-cad
 ence imaging in the chromospheric Ca II K filter of the Visible Broadband 
 Imager reveals signatures of bright arches emanating radially from the loc
 ations of G-band bright points. The G-band bright points denote small-scal
 e magnetic elements harboring strong magnetic fields (~kGauss). Comparison
  with 3-D simulations suggest that the traveling bright arches are acousti
 c waves or shock fronts\, triggered by the movements of magnetic elements.
  Inspecting several examples of the events we indeed see the photospheric 
 bright points changing their appearance and position\, indicating either a
  horizontal movement\, perhaps swaying\, or rotation and seem to be the so
 urce location for the bright arches.\n\nhttps://meetings.aip.de/event/24/c
 ontributions/316/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/316/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Coronal voids and their magnetic nature
DTSTART;VALUE=DATE-TIME:20230509T080000Z
DTEND;VALUE=DATE-TIME:20230509T081500Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-311@meetings.aip.de
DESCRIPTION:Speakers: Jonathan David Nölke (Max Planck Institute for Sola
 r System Research)\nExtreme ultraviolet (EUV) observations of the quiet su
 n corona have revealed extended regions of reduced emission. These coronal
  voids are on average around 30% less intense than the quiet Sun and can h
 ave sizes corresponding to several supergranular cells. At least the large
 r of these voids can exist for many hours with their boundaries to the qui
 et Sun remaining more or less unchanged. The aim of our study is to unders
 tand what causes the reduced emission through an investigation of the unde
 rlying magnetic features in the photopshere. \n\nAt least two scenarios co
 uld explain why the voids appear dark: \n(1) The coronal voids could be ma
 gnetic structures that are (locally) open similar to coronal holes and app
 ear dark for the same reason as those do. (2) they could also be areas of 
 lower (magnetic) heating due to lower magnetic field strength in the photo
 sphere below\, when compared to the typical quiet Sun.\n\nTo distinguish b
 etween the two scenarios\, we combine quiet Sun data from the high-resolut
 ion EUV-channel at 17.4 nm of the Extreme Ultraviolet Imager (EUI)\, showi
 ng coronal plasma close to 1 MK\, and magnetograms obtained with the high-
 resolution telescope of the Polarimetric and Helioseismic Imager (PHI)\, b
 oth onboard Solar Orbiter. \n\nOur results show the average unsigned magne
 tic field inside the voids to be reduced by $\\sim$ 25% with respect to th
 e entire observed quiet Sun region. Specifically\, there is little or no n
 etwork structure visible inside the coronal voids. Observed flux imbalance
 s are within the range of flux imbalances found in quiet Sun areas of simi
 lar size. Hence\, the flux imbalances we find in the voids are not signifi
 cant. Consequently\, it is highly unlikely that these voids are true minia
 ture versions of coronal holes.\nInstead\, we find that in general the uns
 igned magnetic flux in the photosphere below the voids is significantly sm
 aller than in the quiet Sun\, and the vast majority of stronger magnetic p
 atches is located outside the voids. The weaker photospheric field below t
 he voids will produce a Poynting flux smaller than in the surrounding quie
 t Sun. Consequently\, the coronal part above will be heated less and the v
 oids will appear darker in coronal emission.\n\nWe started a subsequent st
 udy into the temporal evolution of coronal voids on time scales from hours
  to several days. Our initial results for a time scale of a few hours indi
 cate that at least larger structures persist\, and their outer boundaries 
 remain mostly unchanged during this time.\n\nhttps://meetings.aip.de/event
 /24/contributions/311/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/311/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Non-LTE formation of the widely-used Fe I 6173 Å line
DTSTART;VALUE=DATE-TIME:20230509T074500Z
DTEND;VALUE=DATE-TIME:20230509T080000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-309@meetings.aip.de
DESCRIPTION:Speakers: Smitha Narayanamurthy (Max Planck Institute for Sola
 r System Research)\nThe Fe I 6173 Å line is widely used to observe the so
 lar photosphere by many instruments. This includes the Helioseismic and Ma
 gnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) and the 
 Polarimetric and Helioseismic Imager on board the Solar Orbiter. During an
 alysis\, this line is often assumed to have formed in Local Thermodynamic 
 Equilibrium (LTE) conditions. However\, the UV overionization effects acti
 ng on the iron species has a strong influence on the Fe I abundance\, whic
 h affects the strength of this line\, resulting in departures from LTE. By
  synthesizing the Stokes profiles from snapshot of a three-dimensional mag
 netohydrodynamic simulation of the solar photosphere\, we have carried out
  a detailed investigation on the nature and strength of the non-LTE (NLTE)
  effects. We find that both intensity and polarization profiles can be str
 ongly affected by the NLTE effects\, and that these effects survive even w
 hen the profiles are averaged spatially or sampled on a coarse wavelength 
 grid such as that used by the SDO/HMI and other magnetographs. Based on th
 e nature of departures from LTE\, treating the 6173 Å line in LTE will li
 kely result in an overestimation of temperature and an underestimation of 
 the magnetic field strength.\n\nhttps://meetings.aip.de/event/24/contribut
 ions/309/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/309/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Photospheric MHD simulations: From sub-granular scales to active r
 egions
DTSTART;VALUE=DATE-TIME:20230509T070000Z
DTEND;VALUE=DATE-TIME:20230509T073000Z
DTSTAMP;VALUE=DATE-TIME:20240704T115555Z
UID:indico-contribution-60-362@meetings.aip.de
DESCRIPTION:Speakers: Matthias Rempel (High Altitude Observatory\, Nationa
 l Center for Atmospheric Research)\nMore than 20 years ago most photospher
 ic MHD simulations focused primarily on small patches of granulation with 
 moderate numerical resolution. Over the past 2 decades advances in computi
 ng infrastructure have enabled photospheric MHD simulations to cover most 
 magnetic environments from quiet Sun to active Sun. In this talk I review 
 these recent developments and focus primarily on simulations that cover th
 e extreme ends of the spectrum: (1) Small-scale dynamo simulations of quie
 t Sun magnetism and (2) Simulations of active region scales. (1) Recent re
 search (observations and modeling) supports the view that the origin of sm
 all-scale magnetism is mostly due to a small-scale dynamo that operates in
 dependently from the large-scale dynamo responsible for the solar cycle. R
 ecent simulations have shown that the saturation field strength and struct
 ure of the resulting magnetic field in the photosphere depend critically o
 n the contributions from deep and shallow recirculation within the strongl
 y stratified convection zone. Therefore\, the small-scale dynamo is not re
 stricted to the photosphere and involves a wide range of scales. Recent re
 search suggests that small-scale magnetic fields may play a critical role 
 for convection zone dynamics. Outstanding questions concern the role of th
 e magnetic Prandtl number\, which will require in the future simulations w
 ith better resolution (\n\nhttps://meetings.aip.de/event/24/contributions/
 362/
LOCATION:Haus H\, Telegrafenberg
URL:https://meetings.aip.de/event/24/contributions/362/
END:VEVENT
END:VCALENDAR