Thumbnail
Access Restriction
Open

Author Fleishman, Gregory D. ♦ Nita, Gelu M. ♦ Gary, Dale E.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ ACCELERATION ♦ COSMIC X-RAY SOURCES ♦ DETECTION ♦ ELECTRONS ♦ EMISSION ♦ EXTRAPOLATION ♦ INTERPLANETARY SPACE ♦ MAGNETIC FIELDS ♦ PLUMES ♦ RADIOWAVE RADIATION ♦ SIMULATION ♦ SOLAR FLARES ♦ SOLAR SYSTEM ♦ SUN ♦ WAVELENGTHS
Abstract Ever-increasing multi-frequency imaging of solar observations suggests that solar flares often involve more than one magnetic fluxtube. Some of the fluxtubes are closed, while others can contain open fields. The relative proportion of nonthermal electrons among those distinct loops is highly important for understanding energy release, particle acceleration, and transport. The access of nonthermal electrons to the open field is also important because the open field facilitates the solar energetic particle (SEP) escape from the flaring site, and thus controls the SEP fluxes in the solar system, both directly and as seed particles for further acceleration. The large-scale fluxtubes are often filled with a tenuous plasma, which is difficult to detect in either EUV or X-ray wavelengths; however, they can dominate at low radio frequencies, where a modest component of nonthermal electrons can render the source optically thick and, thus, bright enough to be observed. Here we report the detection of a large-scale “plume” at the impulsive phase of an X-class solar flare, SOL2001-08-25T16:23, using multi-frequency radio data from Owens Valley Solar Array. To quantify the flare’s spatial structure, we employ 3D modeling utilizing force-free-field extrapolations from the line of sight SOHO /MDI magnetograms with our modeling tool GX-Simulator. We found that a significant fraction of the nonthermal electrons that accelerated at the flare site low in the corona escapes to the plume, which contains both closed and open fields. We propose that the proportion between the closed and open fields at the plume is what determines the SEP population escaping into interplanetary space.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2017-08-20
Publisher Place United States
Journal Astrophysical Journal
Volume Number 845
Issue Number 2


Open content in new tab

   Open content in new tab