On the plasma quasi-thermal noise in the outer heliosphere

Abstract

The recent paper by Li et al. on electron quasi-thermal noise in the outer heliosphere is flawed. It assumes the plasma drift speed to be much smaller than the electron thermal speed, even though both quantities are of the same order of magnitude in the outer heliosphere inward of the termination shock, because of the low plasma temperature. In this case, the Langmuir wave dispersion equation and the quasi-thermal noise in the antenna frame are completely changed. Furthermore, these calculations neglect the shot noise, which should produce a large contribution below the plasma frequency with the Voyager antennas in the outer heliosphere.

Accepted as Research Note of the AAS (18/03/2024)

References in corpus (3)

• Persistent Plasma Waves in Interstellar Space Detected by Voyager 1
• Weak line discovered by Voyager 1 in the interstellar medium: Quasi-thermal noise produced by very few fast electrons
• Plasma line detected by Voyager 1 in the interstellar medium: Tips and traps for quasi-thermal noise spectroscopy