CO-ANALYSIS OF SOLAR MICROWAVE AND HARD X-RAY SPECTRAL EVOLUTIONS. I. IN TWO FREQUENCY OR ENERGY RANGES

Journal Article · Mon Jun 20 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/734/2/113· OSTI ID:21576599

Qiwu, Song; Guangli, Huang ^[1]; Nakajima, Hiroshi ^[2]

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1. Purple Mountain Observatory, Nanjing 210008 (China)
2. Nobeyama Solar Radio Observatory, Nobeyama, Minamisaku, Nagano 384-1305 (Japan)

Solar microwave and hard X-ray spectral evolutions are co-analyzed in the 2000 June 10 and 2002 April 10 flares, and are simultaneously observed by the Owens-Valley Solar Array in the microwave band and by Yohkoh/Hard X-ray Telescope or RHESSI in the hard X-ray band, with multiple subpeaks in their light curves. The microwave and hard X-ray spectra are fitted by a power law in two frequency ranges of the optical thin part and two photon energy ranges, respectively. Similar to an earlier event in Shao and Huang, the well-known soft-hard-soft pattern of the lower energy range changed to the hard-soft-hard (HSH) pattern of the higher energy range during the spectral evolution of each subpeak in both hard X-ray flares. This energy dependence is actually supported by a positive correlation between the overall light curves and spectral evolution in the lower energy range, while it becomes an anti-correlation in the higher energy range. Regarding microwave data, the HSH pattern appears in the spectral evolution of each subpeak in the lower frequency range, which is somewhat similar to Huang and Nakajima. However, it returns back to the well-known pattern of soft-hard-harder for the overall spectral evolution in the higher frequency range of both events. This frequency dependence is confirmed by an anti-correlation between the overall light curves and spectral evolution in the lower frequency range, but it becomes a positive correlation in the higher frequency range. The possible mechanisms are discussed, respectively, for reasons why hard X-ray and microwave spectral evolutions have different patterns in different energy and frequency intervals.

• OSTI ID: 21576599
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 734; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
79 ASTRONOMY AND ASTROPHYSICS
CORRELATIONS
ELECTROMAGNETIC RADIATION
ENERGY DEPENDENCE
EVOLUTION
FREQUENCY DEPENDENCE
HARD X RADIATION
IONIZING RADIATIONS
MICROWAVE RADIATION
MICROWAVE SPECTRA
RADIATIONS
SOLAR ACTIVITY
SOLAR FLARES
SOLAR RADIATION
SPECTRA
STELLAR ACTIVITY
STELLAR FLARES
STELLAR RADIATION
X RADIATION
X-RAY SPECTRA