Observation of wake‐induced plasma waves around an ionospheric sounding rocket

Abstract

Plasma waves generated around the plasma wake of a supersonically moving rocket are studied using data from an impedance probe and a wave receiver installed on the sounding rocket S-520-26. These instruments were used to measure the electron number density and plasma waves at 260 ms intervals, which allows four to five measurements per rotation. During the flight of the S-520-26, three types of plasma waves were observed: short-wavelength electrostatic waves such as electrostatic electron cyclotron harmonic waves, upper hybrid resonance mode waves, and whistler mode waves, assuming that the observed waves are produced in the near wake of the rocket. The wave generation mechanisms are discussed by calculating the linear growth rates of electrostatic waves; positive growth rates are obtained with the assumption of an anisotropic electron distribution function having a beam component or temperature anisotropy. We revealed the spatial distribution of the wave activity around the rocket and its relationship with the wake structure by analysis of the spin-phase dependence of the waves and the observed electron number density. The spin-phase dependence suggests that there are localized hot plasmas around the wake structure that can induce various types of plasma instability.

Numerical simulations of a sounding rocket in ionospheric plasma: Effects of magnetic field on the wake formation and rocket potential

“…Due to accessibility, lower parts of the Earth's ionosphere can be studied in situ only with sounding rockets. Over several decades, many sounding rocket experiments have been performed which allowed for in situ measurements of plasma density, temperature, drift velocities, or electromagnetic fields and improved our understanding of many processes in the ionosphere [ Oya , ; Svenes et al , ; Yamamoto , ; Endo et al , ; Moen et al , ; Spicher et al , ; Lorentzen et al , ; Oksavik et al , ].…”

“…This may lead to disturbances in the vicinity of the rocket, and examples of those are wake formation and sheath effects [ Al'pert et al , ; Liu , ]. In situ measurements of ionospheric plasma density and temperature by Langmuir probes installed on sounding rockets or satellites are, in certain situations, perturbed by the presence of the rapidly moving rocket or satellite itself [ Svenes et al , ; Svenes and Trøim , ; Endo et al , ]. However, because of the complexity of the problem of the plasma‐object interaction, most of the theoretical analysis is limited to simplified and idealized conditions [ Hastings , ].…”

Evidence that Interaction with the Spacecraft Plasma Wake Generates Plasma Waves Close to the Electron Cyclotron Frequency in the Near-Sun Solar Wind

“…Many prior studies have reported data analysis and/or simulation results demonstrating the generation of plasma waves by interaction between a spacecraft and a flowing plasma (e.g., Keller et al 1997;Singh 2000;Guio & Pécseli 2005;Endo et al 2015;Miyake et al 2020). Some of these studies have specifically identified wake-driven waves near the electron cycltron frequency (Singh 2000;Endo et al 2015). However, these prior studies were conducted for plasma flows and magnetization conditions significantly different from those encountered by the Parker Solar Probe (PSP).…”

Wake Potential and Wake Effects on the Ionospheric Plasma Density Measurements With Sounding Rockets

“…There is a limited in situ data on the wake structures, which could allow to perform detailed qualitative and quantitative studies on such wakes. However, sounding rockets with instruments mounted on booms can provide unique possibility to characterize the wake structure (Darian et al, ; Endo et al, ; Svenes et al, ).…”