Parker Solar Probe Evidence for Scattering of Electrons in the Young Solar Wind by Narrowband Whistler-mode Waves
Parker Solar Probe Evidence for Scattering of Electrons in the Young Solar Wind by Narrowband Whistler-mode Waves
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DOI：
10.3847/2041-8213/abefdd
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发表时间：
2021-04-01
影响因子：
7.9
通讯作者：
Pulupa, M.
中科院分区：
文献类型：
--
作者：
Cattell, C.;Breneman, A.;Pulupa, M.
Fields Suite对等离子体波的观测，以及太阳风电子Alpas和Parker太阳探测器上质子研究的电子观测，提供了在径向距离小于0.3Au的窄带哨声模波对Strahl能电子的俯仰角散射的强有力证据。我们给出了两个示例间隔，每个间隔几个小时，其中包括8个带有哨声模波的波形捕获和26个典型的电子分布，这些都得到了详细的研究。两个是窄的，17个是明显加宽的，8个是非常宽的。两个窄的Strahl波发生在没有哨声或非常间断的低幅度波的情况下。在八个最广泛的分布中，有六个与强烈的、持续时间较长的波有关。大约一半的观察到的电子分布具有与能量相关的散射机制一致的特征，这可以从与窄带波的相互作用中得到预期。哨声模式频带中的波功率与俯仰角宽度的比较以及各向异性的测量为哨声模式波的电子散射提供了额外的证据。我们根据观察到的展宽的波动特性和能量来估计共振的范围。这些观测提供了强有力的证据，证明窄带哨声模波散射Strahl能电子产生晕并减少电子热流。
Observations of plasma waves by the Fields Suite and of electrons by the Solar Wind Electrons Alphas and Protons Investigation on the Parker Solar Probe provide strong evidence for pitch angle scattering of strahl-energy electrons by narrowband whistler-mode waves at radial distances less than similar to 0.3 au. We present two example intervals of a few hours each that include eight waveform captures with whistler-mode waves and 26 representative electron distributions that are examined in detail. Two were narrow, seventeen were clearly broadened, and eight were very broad. The two with narrow strahl occurred when there were either no whistlers or very intermittent low amplitude waves. Six of the eight broadest distributions were associated with intense, long duration waves. Approximately half of the observed electron distributions have features consistent with an energy-dependent scattering mechanism, as would be expected from interactions with narrowband waves. A comparison of the wave power in the whistler-mode frequency band to pitch angle width and a measure of anisotropy provides additional evidence for electron scattering by whistler-mode waves. We estimate the range of resonances based on the wave properties and energies over which broadening is observed. These observations provide strong evidence that the narrowband whistler-mode waves scatter strahl-energy electrons to produce the halo and to reduce the electron heat flux.