Radio signature of fragmented electron injection into a coronal loop
Radio signature of fragmented electron injection into a coronal loop
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碎片电子注入日冕环的无线电特征
DOI：
10.1007/bf00712513
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Y. Yurovsky
中科院分区：
文献类型：
--
作者：
G. Fleishman;A. Stepanov;Y. Yurovsky
介绍了 1991 年 11 月 17 日 07:04 UT 在 2.5 和 2.85 GHz 的一个不寻常事件的高时间分辨率观测结果。该事件展示了复杂的时间结构，包括突然减少和关于各种“零”水平的准周期脉动。结果表明，向上注入 > 100 keV 电子束填充损耗锥可以产生突然减小（约 30–100 ms）。在这种情况下，加速在数密度n> 2.5 × 1010cm-3 的致密等离子体层中进行。分段注入的最短时间尺度为 30 ms。考虑了由于波-粒子和波-波相互作用而产生的几种不同的脉动状态。朗缪尔波在不同稳态水平下的非线性振荡的理论机制提供了与观测到的脉动的最佳一致性。第二系列脉动的稳态水平降低与填充损失锥的电子的长（准连续）注入有关，这降低了波能水平。获得了无线电源的物理参数。另一方面，ECM 非线性脉动似乎是在 dMe 星中观察到的射电脉动的原因。
High-time-resolution observations of an unusual event of 1991 November 17, 07:04 UT at 2.5 and 2.85 GHz are presented. The event demonstrates sophisticated tine time structure including sudden reductions and quasi-periodic pulsations about various ‘zero’ levels. It is shown that the sudden reductions (≈30–100 ms) can be produced with upward-injected > 100 keV electron beams filling the loss-cone. In such a case the acceleration is proceeding in a dense plasma layer with number densityn> 2.5 × 1010cm−3. The shortest time scale of the fragmented injection isтinjmin≈ 30 ms. Several different pulsating regimes arising due to the wave-particle and wave-wave interactions are considered. A theoretical mechanism with the nonlinear oscillations of Langmuir waves at the different steady-state levels provides the best agreement with the observed pulsations. The reduced steady-state level of the second train of pulsations is connected with the long (quasi-continuous) injection of electrons filling the loss-cone, which reduced the wave energy level. Physical parameters of the radio source were obtained. On the other hand, ECM nonlinear pulsations seem to be responsible for the radio pulsations observed in dMe stars.