Inhibition of type III radio emissions due to the interaction between two electron beams: Observations and simulations
Inhibition of type III radio emissions due to the interaction between two electron beams: Observations and simulations
复制标题
由于两束电子束之间的相互作用而抑制 III 型无线电发射：观察和模拟
DOI：
10.1002/2013ja019688
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
S. Hoang
中科院分区：
文献类型：
--
作者：
C. Briand;P. Henri;S. Hoang
我们报告了在太阳风中观察到的两个 III 型爆发的特殊相互作用。当电子束在相同的磁场线上传播时，会观察到 III 型无线电发射的惊人损耗。我们将 STEREO 任务上 WAVES 实验的观测结果与动力学等离子体模拟结合起来，研究两束电子束之间相互作用所产生的 III 型无线电发射的消光。远程观测能够跟踪行星际介质中的电子束，并表明辐射无线电波的水平在电子束穿过后恢复。光束驱动朗缪尔波的原位观测为朗缪尔衰变提供了证据。密度波动是从现场观测中提取的。光束的速度是根据衰减朗缪尔波的现场观测和远程无线电观测独立评估的。动力学模拟表明，当两束光束交叉时，光束驱动的朗缪尔波的水平会降低。我们表明，慢光束引起快光束的拟线性弛豫的强烈减少，限制了生成的朗缪尔波的振幅。此外，在两束电子束的情况下，朗缪尔波相干性的缺乏降低了朗缪尔参量衰减的效率。因此，我们得出结论，所观察到的 III 型无线电发射的损耗与无线电发射机制无关，只要它取决于朗缪尔幅度和相干性。
We report the peculiar interaction of two type III bursts observed in the solar wind. As electron beams propagating on the same magnetic field lines cross, a spectacular depletion of the type III radio emission is observed. We combine observations from the WAVES experiment on board the STEREO mission together with kinetic plasma simulations to study the extinction of type III radio emission resulting from the interaction between two electron beams. The remote observations enable to follow the electron beams in the interplanetary medium and show that the level of radiated radio waves is recovered after the beam crossing. The in situ observations of beam‐driven Langmuir waves give evidence for Langmuir decay. The density fluctuations are extracted from in situ observations. The velocity of the beams is independently evaluated from in situ observations of decaying Langmuir waves and remote radio observations. The kinetic simulations show that the level of beam‐driven Langmuir waves is reduced as the two beams cross. We show that the slow beam induced a strong reduction of the quasilinear relaxation of the fast beam, limiting the amplitude of the generated Langmuir waves. Moreover, in the case of two electron beams, the lack of Langmuir wave coherence reduces the efficiency of the Langmuir parametric decay. We thus conclude that the observed depletion of the type III radio emission is independent of the radio emission mechanism, as long as it depends on the Langmuir amplitude and coherence.