Type III bursts observations in the heliosphere: progress and challenges

Vratislav Krupar, USRA-NASA/GSFC-IAP/CAS

Type III bursts are fast drifting emissions generated by suprathermal electron beams originated from magnetic reconnection sites of solar flares. Although type III bursts generated in the solar corona are routinely measured from the ground, spacecraft observations of those originating further from the Sun are necessary as the ionosphere blocks radio signal in the decametric and hectometric ranges. Over the last decade, we have benefited from multipoint radio measurements obtained by the twin-spacecraft STEREO mission, which also allow us to localize radio sources in the solar wind. Since propagation of radio waves is strongly affected by random electron density fluctuations, type III bursts provide us with a unique diagnostic tool for solar wind remote plasma measurements. One of the current challenges in solar radio astronomy is to disentangle real source properties of solar radio bursts from wave propagation effects.