High spectral resolution measurements of a solar flare hard X-ray burst

Journal Article · Thu Jan 01 04:00:00 EST 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/164891· OSTI ID:6570949

Lin, R P; Schwartz, R A

Observations are reported of an intense solar flare hard X-ray burst on June 27, 1980, made with a balloon-borne array of liquid nitrogen-cooled Ge detector which provided unprecedented spectral resolution (no more than 1 keV FWHM). The hard X-ray spectra throughout the impulsive phase burst fitted well to a double power-law form, and emission from an isothermal 0.1-1 billion K plasma can be specifically excluded. The temporal variations of the spectrum indicate that the hard X-ray burst is made up of two superposed components: individual spikes lasting about 3-15 sec, which have a hard spectrum and a break energy of 30-65 keV; and a slowly varying component characterized by a soft spectrum with a constant low-energy slope and a break energy which increases from 25 kev to at least 100 keV through the event. The double power-law shape indicates that DC electric field acceleration, similar to that occurring in the earth's auroral zone, may be the source of the energetic electrons which produce the hard X-ray emission. 39 references.

• Research Organization: California Univ., Berkeley; NASA, Goddard Space Flight Center, Greenbelt, MD
• OSTI ID: 6570949
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 312; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
ELECTROMAGNETIC RADIATION
HARD X RADIATION
IONIZING RADIATIONS
MEASURING INSTRUMENTS
RADIATION DETECTORS
RADIATIONS
SOLAR ACTIVITY
SOLAR FLARES
SOLAR X-RAY BURSTS
SPECTRA
X RADIATION
X-RAY SPECTRA