作者: Lily Kromyda , David Malaspina , Robert Ergun , Jaye Verniero , Lynn Wilson
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摘要: In this study we present observations and report on statistical properties of a persistent electrostatic wave signature seen in the Parker Solar Probe AC electric field spectra. In low-cadence (~ 1 s) continuous coverage spectra these waves appear broad-band. High-cadence (~ 7 ms) limited coverage spectra reveal them to last for fractions of a second, and have frequencies that shift on millisecond timescales, in a continuously upward, downward or inverted U-shape trend. Through the use of a detection algorithm we are able to identify these frequency-dispersed waves (FDWs) in low-cadence E-field spectra and analyze them statistically. We find that the orientation of their electric field is parallel to the background magnetic field. Their occurrence, frequency and total wave power with respect to distance from the Sun shows an intermittent character. We carry out a parameter study in an effort to identify what controls …