BENCHMARKING FAST-TO-ALFVÉN MODE CONVERSION IN A COLD MHD PLASMA. II. HOW TO GET ALFVÉN WAVES THROUGH THE SOLAR TRANSITION REGION
BENCHMARKING FAST-TO-ALFVÉN MODE CONVERSION IN A COLD MHD PLASMA. II. HOW TO GET ALFVÉN WAVES THROUGH THE SOLAR TRANSITION REGION
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冷 MHD 等离子体中快速到 ALFVÉN 模式转换的基准测试 II。
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
P. Cally
中科院分区：
文献类型：
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作者：
Shelley C. Hansen;P. Cally
由于电离分数低，阿尔文波可能难以在光球层激发，并且在过渡区 (TR) 遭受近全反射。然而它们在日冕和日光层中无处不在。为了克服这些困难，我们表明它们可能通过反射快速磁流体动力波的转换而在色球层的高处产生，并且如果快反射点位于TR的几个尺度高度内，则Alfvénic TR反射会大大减少。还探讨了模式转换对反射快波相位的影响。该阶段可能会被误解为行进速度扰动，这对活动区域的实际地震探测有影响。
Alfvén waves may be difficult to excite at the photosphere due to low-ionization fraction and suffer near-total reflection at the transition region (TR). Yet they are ubiquitous in the corona and heliosphere. To overcome these difficulties, we show that they may instead be generated high in the chromosphere by conversion from reflecting fast magnetohydrodynamic waves, and that Alfvénic TR reflection is greatly reduced if the fast reflection point is within a few scale heights of the TR. The influence of mode conversion on the phase of the reflected fast wave is also explored. This phase can potentially be misinterpreted as a travel speed perturbation with implications for the practical seismic probing of active regions.