We study the non-thermal emissions in a solar flare occurring on 2003 May 29 by using RHESSI hard X-ray (HXR) and Nobeyama microwave observations. This flare shows several typical behaviors of the HXR and microwave emissions: time delay of microwave peaks relative to HXR peaks, loop-top microwave and footpoint HXR sources, and a harder electron energy distribution inferred from the microwave spectrum than from the HXR spectrum. In addition, we found that the time profile of the spectral index of the higher-energy ($\gsim 100$ keV) HXRs is similar to that of the microwaves, and is delayed from that of the lower-energy ($\lsim 100$ keV) HXRs. We interpret these observations in terms of an electron transport model called {\TPP}. We numerically solved the spatially-homogeneous {\FP} equation to determine electron evolution in energy and pitch-angle space. By comparing the behaviors of the HXR and microwave emissions predicted by the model with the observations, we discuss the pitch-angle distribution of the electrons injected into the flare site. We found that the observed spectral variations can qualitatively be explained if the injected electrons have a pitch-angle distribution concentrated perpendicular to the magnetic field lines rather than isotropic distribution.
Solar neutrons have been detected using the neutron monitor located at Mt. Chacaltaya, Bolivia, in association with a large solar flare on November 24, 2000. This is the first detection of solar neutrons by the neutron monitor that have been reported so far in solar cycle 23. The statistical significance of the detection is 5.5 sigma. In this flare, the intense emission of hard X-rays and gamma-rays has been observed by the Yohkoh Hard X-ray Telescope (HXT) and Gamma Ray Spectrometer (GRS), respectively. The production time of solar neutrons is better correlated with those of hard X-rays and g…
Comparative study of the inial spikes of SGR giant flares in 1998 and 2004 observed with GEOTAIL: Do magnetospheric instabilities trigger large scale fracturing of magnetar's crust?
本文给出了1998年8月27日SGR 1900+14大耀斑的不饱和峰形.这是由GEOTAIL航天器上低能粒子仪器的粒子计数器获得的。所观察到的峰形揭示了四个特征结构:初始陡峭的上升,中间上升到峰值,指数衰减和小驼峰在衰减阶段。从该光变曲线,我们发现各向同性峰值亮度为$2.3\times10^{46}$ erg s $^{-1}$,总能量为$4.3 \times 10^{44}$ erg s $^{-1}$($E\gtrsim$ 50 keV),假设到SGR 1900+14的距离为15 kpc,光谱为光学薄的热韧致辐射,$kT =$ 240 keV。这些都是一致的,与以前报道的下限来自于ESTA和Konus-Wind观测。对1998年SGR 1900+14和2004年SGR 1806-20的初始尖峰进行了对比研究。初始急剧上升的时间尺度表明其起源于磁层,而中间上升到峰值的时间尺度表明其起源于地壳破裂。最后,我们认为,这四个结构和相应的时间尺度提供了一个线索,以确定河外SGR巨型耀斑之间的短伽玛暴。
源自太阳黑子的强烈太阳耀斑会产生高能粒子(质子,$α$),卫星和地面探测器都能很好地观测到。耀斑爆发产生不同能量带的信号(射电、X射线、伽马射线和中子)。最强大的太阳耀斑发生在1956年2月23日,1989年9月29日和最近的10月28日,2003年11月2日,4日,13日在尖锐的时间释放最大的耀斑能量(${E}_{FL} \simeq {10}^{31}÷{10}^{32} erg). The high energy solar flare protons scatter within the solar corona and they must be source of a prompt neutrino burst through the production of charged pions. Later on, solar flare particles hitting the atmosphere may marginally increase the atmospheric neutrino flux. The prompt solar neutrino flare may be detected in the largest underground $ ν $ detectors. Our estimate for the October - November 20…