Stochastic diffusion of electrons interacting with whistler-mode waves in the solar wind

Abstract

Effects of increasing whistler amplitude and propagation angle are studied through a variational test particle simulation and calculations of the resonance width. While high amplitude and oblique whistlers in typical 1 AU solar wind parameters are capable of forming an isotropic population without any additional processes, anomalous interactions with quasi-parallel whistlers may be essential to the process of halo formation near the Sun. High amplitude and quasi-parallel whistlers can scatter strahl electrons to low velocities (less than the wave phase velocity) to form a halo population, as long as their amplitude is sufficiently high. We also present in detail a careful treatment of the sensitivity to initial conditions based on calculations of the phase space volume, which is necessary for numerical calculations of highly stochastic motion due to resonant interactions with large amplitude waves. Our method ensures that the volume-preserving characteristic of the Boris algorithm is consistently applied for simulations of both stochastic and non-stochastic particle motion.

11 pages, 5 figures, published in Physics of Plasmas

References in corpus (10)

• Electrons in the Young Solar Wind: First Results from the Parker Solar Probe
• Whistler mode waves and the electron heat flux in the solar wind: Cluster observations
• Statistical Study of Whistler Waves in the Solar Wind at 1 AU
• Scattering of Strahl Electrons in the Solar Wind between 0.3 and 1 au: Helios Observations
• Suppression of electron thermal conduction by whistler turbulence in a sustained thermal gradient
• Whistler wave generation by halo electrons in the solar wind
• Alternative high plasma beta regimes of electron heat-flux instabilities in the solar wind
• On the role of solar wind expansion as a source of whistler waves: scattering of suprathermal electrons and heat flux regulation in the inner heliosphere
• Parker Solar Probe evidence for scattering of electrons in the young solar wind by narrowband whistler-mode waves
• Modeling interactions of narrowband large amplitude whistler-mode waves with electrons in the solar wind inside ~.3 AU and at 1 AU using a particle tracing code

Cited by in corpus (5)

• Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum
• Whistler waves generated inside magnetic dips in the young solar wind: observations of the Search-Coil Magnetometer on board Parker Solar Probe
• The aperiodic firehose instability of counter-beaming electrons in space plasmas
• Whistler waves in the young solar wind: statistics of amplitude and propagation direction from Parker Solar Probe Encounters 1-11
• The Heliospheric Ambipolar Potential Inferred from Sunward-Propagating Halo Electrons