Tool kit for antennae and thermal noise near the plasma frequency

TLDR

The paper offers tools to rapidly compute the quasi‑thermal noise spectrum or impedance of electric antennas near the plasma frequency for space‑plasma calibration and diagnostics. The authors present analytical formulas and numerical results for wire or sphere dipoles in isotropic plasmas with one or two Maxwellian electron populations, including particle collection/emission effects and extensions to complex geometries, drifting, or magnetized plasmas. The study concludes with design guidelines and data‑interpretation insights for plasma‑wave experiments.

Abstract

This paper provides the essential tools for deriving quickly the quasi‐thermal noise spectrum or the impedance of a given electric antenna near the plasma frequency, for calibration or diagnosis in space plasmas. We give simple analytical expressions and numerical results for either wire or sphere dipoles in an isotropic plasma with one or two Maxwellian electron populations. We include the contribution of the particles collected and/or emitted by the antenna surface. We also indicate some modifications brought about by using more complicated antenna geometries, and a drifting or a magnetized plasma. Finally, we give some conclusions for antenna design or data interpretation in plasma wave experiments.