2018/12/24 by N. L. S. Jeffrey, L. Fletcher, N. Labrosse +1 · 4 citations
Physics and Astronomy · #astro-ph.SR
paper · pdf · doi:10.1126/sciadv.aav2794
published as Science Advances 05 Dec 2018: Vol. 4, no. 12, eaav2794 · Published in Science Advances (5th December 2018)
arxiv created 2018/12/24 · arxiv updated 2018/12/27
We present the first observational study of the onset and evolution of solar flare turbulence in the lower solar atmosphere on an unprecedented time scale of 1.7 s using the Interface Region Imaging Spectrograph observing plasma at a temperature of 80,000 K. At this time resolution, nonthermal spectral line broadening, indicating turbulent velocity fluctuations, precedes the flare onset at this temperature and is coincident with net blue-shifts. The broadening decreases as the flare brightens and then oscillates with a period of ~10 s. These observations are consistent with turbulence in the lower solar atmosphere at the flare onset, heating that region as it dissipates. This challenges the current view of energy release and transport in the standard solar flare model, suggesting that turbulence partly heats the lower atmosphere.