Whistler Wave Observations by \textit{Parker Solar Probe} During Encounter $1$: Counter-Propagating Whistlers Collocated with Magnetic Field Inhomogeneities and their Application to Electric Field Measurement Calibration

Abstract

Observations of the young solar wind by the Parker Solar Probe (PSP) mission reveal the existence of intense plasma wave bursts with frequencies between $0.05$ -- $0.20f_{\mathrm{ce}}$ (tens of Hz up to $\sim 300$ Hz) in the spacecraft frame. The wave bursts are often collocated with inhomogeneities in the solar wind magnetic field, such as local dips in magnitude or sudden directional changes. The observed waves are identified as electromagnetic whistler waves that propagate either sunward, anti-sunward, or in counter-propagating configurations during different burst events. Being generated in the solar wind flow the waves experience significant Doppler down-shift and up-shift {of wave frequency} in the spacecraft frame for sunward and anti-sunward waves, respectively. Their peak amplitudes can be larger than $2$~nT, where such values represent up to $10\%$ of the background magnetic field during the interval of study. The amplitude is maximum for propagation parallel to the background magnetic field. We (i) evaluate the properties of these waves by reconstructing their parameters in the plasma frame, (ii) estimate the effective length of the PSP electric field antennas at whistler frequencies, and (iii) discuss the generation mechanism of these waves.

References in corpus (6)

• The Solar Probe Cup on Parker Solar Probe
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Cited by in corpus (4)

• Quantifying the diffusion of suprathermal electrons by whistler waves between 0.2 and 1 AU with Solar Orbiter and Parker Solar Probe
• Whistler waves in the young solar wind: statistics of amplitude and propagation direction from Parker Solar Probe Encounters 1-11
• Reconstruction of Polarization Properties of Whistler Waves From Two Magnetic and Two Electric Field Components: Application to Parker Solar Probe Measurements
• Probing Solar Wind Structures with Solar Energetic Particle Observations from Solar Orbiter