RESIK and RHESSI observations of the 20 September 2002 flare
RESIK and RHESSI observations of the 20 September 2002 flare
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DOI：
10.1051/0004-6361/202038434
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发表时间：
2020-08
影响因子：
6.5
通讯作者：
A. Kępa;R. Falewicz;M. Siarkowski;M. Pietras
中科院分区：
文献类型：
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作者：
A. Kępa;R. Falewicz;M. Siarkowski;M. Pietras
上下文。来自CORONAS-F上RESIK仪器的软x射线光谱（3.33 Å-6.15 Å）构成了研究太阳耀斑等离子体物理条件的独特数据库，使差分发射测量的计算成为可能。两个最短波长的RESIK通道与Ramaty高能太阳光谱成像仪（RHESSI）光谱能量范围的下端重叠，位于3 keV左右，使得比较两个数据集成为可能。目标。我们的目的是比较来自RESIK和RHESSI光谱仪的观测结果，并交叉关联这些仪器。将观测结果与基于一维流体动力学（1D-HD）模拟结果计算的合成光谱进行了比较。对2002年9月20日（SOL2002-09-20T09:28）的耀斑进行了分析。方法。我们根据RHESSI和太阳和日光层天文台上的极紫外成像望远镜的图像估计了耀斑环的几何形状，这是1D-HD建模所必需的。用RHESSI谱测定了非热电子的分布。1D-HD模型假设具有幂律谱的非热电子被注入到耀斑环的顶端。然后nte加热并蒸发色球层，使热而致密的等离子体以软x射线的形式辐射到环中。通过比较地球静止业务环境卫星1-8 Å数据的观测通量和计算通量，限制了电子的总能量。我们确定了耀斑演变过程中耀斑环上每一点的温度和密度，并计算了由此产生的x射线光谱。结果。根据2002年9月20日耀斑流体动力学模拟结果计算的合成光谱与观测到的RESIK光谱在耀斑持续时间的大部分时间内的一致性在2倍以内。这种差异因素可能与RESIK和RHESSI仪器之间交叉校准的不确定度有关。
Context. Soft X-ray spectra (3.33 Å–6.15 Å) from the RESIK instrument on CORONAS-F constitute a unique database for the study of the physical conditions of solar flare plasmas, enabling the calculation of differential emission measures. The two RESIK channels for the shortest wavelengths overlap with the lower end of the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) spectral energy range, which is located around 3 keV, making it possible to compare both data sets. Aims. We aim to compare observations from RESIK and RHESSI spectrometers and cross-correlate these instruments. Observations are compared with synthetic spectra calculated based on the results of one-dimensional hydrodynamical (1D-HD) modelling. The analysis was performed for the flare on 20 September 2002 (SOL2002-09-20T09:28). Methods. We estimated the geometry of the flaring loop, necessary for 1D-HD modelling, based on images from RHESSI and the Extreme-Ultraviolet Imaging Telescope aboard the Solar and Heliospheric Observatory. The distribution of non-thermal electrons (NTEs) was determined from RHESSI spectra. The 1D-HD model assumes that non-thermal electrons with a power-law spectrum were injected at the apex of the flaring loop. The NTEs then heat and evaporate the chromosphere, filling the loop with hot and dense plasma radiating in soft X-rays. The total energy of electrons was constrained by comparing observed and calculated fluxes from Geostationary Operational Environmental Satellite 1–8 Å data. We determined the temperature and density at every point of the flaring loop throughout the evolution of the flare, calculating the resulting X-ray spectra. Results. The synthetic spectra calculated based on the results of hydrodynamic modelling for the 20 September 2002 flare are consistent within a factor of two with the observed RESIK spectra during most of the duration of the flare. This discrepancy factor is probably related to the uncertainty on the cross-calibration between RESIK and RHESSI instruments.