Duan, D;
He, J;
Wu, H;
Verscharen, D;
(2020)
Magnetic Energy Transfer and Distribution between Protons and Electrons for Alfvénic Waves at Kinetic Scales in Wavenumber Space.
The Astrophysical Journal
, 896
(1)
, Article 47. 10.3847/1538-4357/ab8ad2.
Preview |
Text
Verscharen_Duan_2020_ApJ_896_47.pdf - Published Version Download (1MB) | Preview |
Abstract
Turbulent dissipation is considered a main source of heating and acceleration in cosmic plasmas. The alternating current Joule-like term, (δj · δE), is used to measure the energy transfer between electromagnetic fields and particles. Because the electric field depends on the reference frame, in which frame to calculate (δj · δE) is an important issue. We compute the scale-dependent energy transfer rate spectrum in wavevector space, and investigate the electric-field fluctuations in two reference frames: δE in the mean bulk flow frame and δE' in the local bulk flow frame (non-inertial reference frame). Considering Alfvénic waves, we find that (δj · δE'), which neglects the contribution of work done by the ion inertial force, is not consistent with the magnetic field energy damping rate (2γδB²) according to linear Maxwell–Vlasov theory, while (δj · δE) is exactly the same as 2γδB² in wavenumber space (k ∥, k ⊥), where γ is the linear damping rate. Under typical conditions of solar wind at 1 au, we find in our theoretical calculation that the field energy is mainly converted into proton kinetic energy leaving the residual minor portion for electrons. Although the electrons gain energy in the direction perpendicular to the mean magnetic field, they return a significant fraction of their kinetic energy in the parallel direction. Magnetic-field fluctuations can transfer particle energy between the parallel and perpendicular degrees of freedom. Therefore, (δj∥ · δE∥) and (δj⊥ · δE⊥) do not solely describe the energy transfer in the parallel direction and perpendicular direction, respectively.
| Type: | Article |
|---|---|
| Title: | Magnetic Energy Transfer and Distribution between Protons and Electrons for Alfvénic Waves at Kinetic Scales in Wavenumber Space |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/1538-4357/ab8ad2 |
| Publisher version: | https://doi.org/10.3847/1538-4357/ab8ad2 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Solar wind; Interplanetary turbulence; Alfvén waves |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10097032 |
Archive Staff Only
 |
View Item |
