| Project/Area Number |
63540186
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Astronomy
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| Research Institution | National Astronomical Observatory |
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Principal Investigator |
KAI Keizo National Astronomical Observatory, Division of Radio Astronomy, Professor, 電波天文学研究系, 教授 (70012846)
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| Co-Investigator(Kenkyū-buntansha) |
小杉 健郎 東京大学, 理学部天文学教育研究センター, 助教授 (70107473)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1989: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1988: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | Solar flare / Solar radio emission / Solar X-ray / High-energy phenomena in the Sun / Particle acceleration in solar flare |
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| Research Abstract |
From the close similarity of time profile between hard Xrays and microwaves emitted in solar flares, it is generally accepted that the two kinds of emission are produced by a common population of energetic electron. However, whether hard X-rays and microwaves are emitted by these electrons while they are precipitating down into the chromosphere (thick-target model) or by these electrons which are trapped in a magnetic field (thin-target model) has long been controversial with respect to both acceleration mechanisms of electrons and emission models.
Using hard X-ray data which have been recorded with the X-ray spectrometer aboard the SMM satellite (NASA) and provided by courtesy of Dr.Dennis and microwave data recorded with polarimeters operating here, we obtained the following result.
(a) Assuming the energy spectrum of electrons to be a power-law, we deduced the power law index independently from X-ray data and radio data. We found that the indices have a loose correlation : that means, both X-rays and microwaves are produces by a common population of electrons.
(b) However, contrary to my expectation, these observed points fall between the line calculated on the thick- target model and that calculated on the thin-target model. We therefore cannot judge which model of the above two models is plausible. This negative result possibly suggests a crucial point which would otherwise be missed.
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