The Parker Solar Probe successfully makes electric field measurements over the frequency range of DC‐100 Hz, thanks to the remarkable symmetry of the antennas with respect to sunlight and the mostly radial magnetic field. Calibration of the electric field measurement is described. Sampled electric and magnetic field data are utilized to determine wave modes of whistlers and Alfven‐ion‐cyclotron waves. In the course of such determinations, the electric field effective antenna length was found to vary with frequency from ~1 m at low frequencies to essentially the antenna half‐geometric length of 3.5 m above 20 Hz. Properties of the low‐frequency electric field power as functions of frequency and radial distance are determined. There is a plateau in the electric field power spectrum above ~10 Hz, which is due to the power in waves exceeding the turbulent cascade power above that frequency. This wave power decreases by one to two orders of magnitude from 35 to 50 solar radii.

中文翻译：

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Parker太阳探头上的直流和低频电场测量

由于天线相对于日光的对称性和主要是径向磁场的影响，Parker太阳探针成功地在DC-100 Hz的频率范围内进行了电场测量。描述了电场测量的校准。采样的电场和磁场数据可用于确定吹哨声和Alfven-ion-回旋加速器波的波模。在进行此类确定的过程中，发现电场有效天线长度随频率的变化而变化，从低频的〜1 m到20 Hz以上的3.5 m的天线半几何长度。确定了低频电场功率随频率和径向距离变化的特性。约10 Hz以上的电场功率谱处于平稳状态，这是由于波浪中的功率超过了该频率之上的湍流级联功率。该波功率从35到50太阳半径减小一到两个数量级。