CORONAL MAGNETOGRAPHY OF A SIMULATED SOLAR ACTIVE REGION FROM MICROWAVE IMAGING SPECTROPOLARIMETRY
CORONAL MAGNETOGRAPHY OF A SIMULATED SOLAR ACTIVE REGION FROM MICROWAVE IMAGING SPECTROPOLARIMETRY
复制标题
微波成像分光偏振法模拟太阳活动区的日冕磁图
DOI：
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发表时间：
2015
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影响因子：
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通讯作者：
S. White
中科院分区：
文献类型：
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作者：
Zhitao Wang;D. Gary;G. Fleishman;S. White
我们模拟了从模型太阳活动区域生成的多个频率的扩展欧文斯谷太阳能阵列 (EOVSA) 无线电图像，嵌入到真实的太阳盘模型中，并探索了不同光谱分析方案的数据立方体，以评估实现 EOVSA 最重要的科学目标之一——日冕磁成像的潜力。在本文中，我们重点对盘上太阳活动区域模型的陀螺谐振和自由-自由发射进行建模，该模型在电子密度、温度和磁场分布方面具有现实的复杂性。我们将折叠 EOVSA 仪器剖面后沿每条视线的图像数据立方体推断出的磁场参数与模型中使用的原始（展开）参数进行比较。我们发现，即使是最容易自动化的基于图像的分析方法（Level-0）也能提供合理的定量结果，尽管它们受到傅里叶（UV）平面中有限采样造成的系统效应的影响。最后，我们注意到由于错误识别的陀螺频率谐波而可能出现错误，并讨论了应用更复杂的基于光谱的分析方案（1 级）的前景，以解决在可以提高紫外线覆盖范围和空间分辨率的情况下的问题。
We have simulated the Expanded Owens Valley Solar Array (EOVSA) radio images generated at multiple frequencies from a model solar active region, embedded in a realistic solar disk model, and explored the resulting data cube for different spectral analysis schemes to evaluate the potential for realizing one of EOVSA’s most important scientific goals—coronal magnetography. In this paper, we focus on modeling the gyroresonance and free–free emission from an on-disk solar active region model with realistic complexities in electron density, temperature and magnetic field distribution. We compare the magnetic field parameters extrapolated from the image data cube along each line of sight after folding through the EOVSA instrumental profile with the original (unfolded) parameters used in the model. We find that even the most easily automated, image-based analysis approach (Level-0) provides reasonable quantitative results, although they are affected by systematic effects due to finite sampling in the Fourier (UV) plane. Finally, we note the potential for errors due to misidentified harmonics of the gyrofrequency, and discuss the prospects for applying a more sophisticated spectrally based analysis scheme (Level-1) to resolve the issue in cases where improved UV coverage and spatial resolution are available.