Tracing of energetic electron beams in solar corona with imaging spectroscopy from MUSER

Susanta Kumar Bisoi, National Astronomical Observatories, Chinese Academy of Sciences, Beijing

The energy release during flare accelerates electrons in solar corona and these energetic electrons propagate along coronal magnetic field lines that appear as rapidly drifting structures in radio dynamic spectra. They are commonly known as Type III bursts. The Type III bursts identified in decimetric frequency range is typically associated with the location of electron acceleration and flare energy release. However, due to the limited imaging available at the decimetric frequency range, the exact location of electron acceleration and so the flare energy release has still remained poorly known. The new radio interferometer Miangtu Spectra Radio Heliograph (MUSER), operating in the frequency range 400-2000 MHz, has provided simultaneous spectral and imaging opportunities at the decimetric frequency range. Here we present MUSER spectral and imaging observations of decimetric Type III bursts with high spectral (25 MHz), spatial (1.3 to 50 arcsec) and temporal (25 ms) resolution. The strong narrow band Type III bursts are identified right at the start of a C2.3 solar flare. Subsequently, few seconds apart, a series of Type III bursts are identified coinciding with hard X-ray (HXR) and microwave radio burst activities. The MUSER images of these Type III bursts show propagation of radio sources along coronal magnetic field lines that located far from the location of HXR and microwave burst sources. Each Type III burst, as revealed by MUSER, show different line of propagation suggesting propagation of varying energetic electrons with different speed. The different source location of each energetic electron beam suggests the existence of multiple reconnection sites with a wide spaced energy release volume indicating that the flare energy release is fragmentary in nature.