Anomalous F region response to moderate solar flares
Anomalous F region response to moderate solar flares
复制标题
F 区对中度太阳耀斑的异常响应
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
R. Schunk
中科院分区：
文献类型：
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作者：
C. Smithtro;J. Sojka;T. Berkey;D. Thompson;R. Schunk
犹他州的熊湖天文台在中度太阳X射线耀斑期间用动态探空仪记录的电离图显示出E和F1区域电离层的特征增强。然而，在这些相同的耀斑期间，电离层的峰值电子密度（NmF2）出乎意料地下降，在耀斑结束后恢复。为了使这种异常行为与总电子含量（TEC）的预期增加相协调，我们使用犹他州州立大学开发的时间依赖电离层模型（TDIM）进行了建模工作。对于太阳输入，使用TIMED航天器上的太阳极紫外实验仪器的测量值创建了一个简单的耀斑时间辐照度模型。TDIM模拟表明，NmF2的异常响应可以解释为假设一个快速的电子温度增加，这增加了O+标度的高度，移动等离子体到更高的高度。模型结果能够再现NmF2的降低以及预期的TEC增强。
Ionograms recorded with a dynasonde at Bear Lake Observatory, Utah, during moderate solar x‐ray flares exhibit characteristic enhancements to the E and F1 region ionosphere. However, during these same flares, the peak electron density of the ionosphere (NmF2) unexpectedly decreases, recovering after the flare ends. In order to reconcile this anomalous behavior with expected increases to the total electron content (TEC), we undertake a modeling effort using the Time‐Dependent Ionospheric Model (TDIM) developed at Utah State University. For solar input, a simple flare time irradiance model is created, using measurements from the Solar EUV Experiment instrument on the TIMED spacecraft. TDIM simulations show that the anomalous NmF2 response can be explained by assuming a rapid electron temperature increase, which increases the O+ scale height, moving plasma to higher altitudes. The model results are able to reproduce both the decreasing NmF2 as well as the expected TEC enhancement.