论文标题
观察粒子能量高于Nyquist频率：现场粒子相关技术的应用
Observing Particle Energization above the Nyquist Frequency: An Application of the Field-Particle Correlation Technique
论文作者
论文摘要
现场粒子相关技术利用单点测量来发现湍流空间等离子体中各种粒子能量机制的特征。通过这种技术，在模拟和地球磁石的观察结果中发现了电子阻尼的签名，但是航天器采样率的工具性限制给发现太阳风中Landau抑制作用的全部程度带来了挑战。理论预测，即使是从相对于波浪阻尼发生的特征频率下采样的数据，野外粒子相关性也可以恢复速度空间的能量特征。为了检验这一假设，我们对空间等离子体湍流进行了高分辨率的陀螺仪模拟，确认它包含电子降水的签名，然后系统地减少数据的时间分解以识别签名无法恢复的点。我们发现结果支持我们的理论预测，并寻找可以与航天器任务的测量能力进行比较的经验法则，以告知将现场颗粒相关性应用于低时间分辨率数据的过程。
The field-particle correlation technique utilizes single-point measurements to uncover signatures of various particle energization mechanisms in turbulent space plasmas. The signature of Landau damping by electrons has been found in both simulations and observations from Earth's magnetosheath using this technique, but instrumental limitations of spacecraft sampling rates present a challenge to discovering the full extent of the presence of Landau damping in the solar wind. Theory predicts that field-particle correlations can recover velocity-space energization signatures even from data that is undersampled with respect to the characteristic frequencies at which the wave damping occurs. To test this hypothesis, we perform a high-resoluation gyrokinetic simulation of space plasma turbulence, confirm that it contains signatures of electron Landau damping, and then systematically reduce the time resolution of the data to identify the point at which the signatures become impossible to recover. We find results in support of our theoretical prediction and look for a rule of thumb that can be compared with the measurement capabilities of spacecraft missions to inform the process of applying field-particle correlations to low time resolution data.
