loading page

Evaluating the de Hoffmann-Teller cross-shock potential at real collisionless shocks
  • +8
  • Steven J. Schwartz,
  • Robert E Ergun,
  • Kucharek Harald,
  • Lynn Bruce Wilson,
  • Li-Jen Chen,
  • Katherine Amanda Goodrich,
  • Drew L. Turner,
  • Imogen Gingell,
  • Hadi Madanian,
  • Daniel J Gershman,
  • Robert J. Strangeway
Steven J. Schwartz
University of Colorado Boulder, University of Colorado Boulder

Corresponding Author:steven.schwartz@lasp.colorado.edu

Author Profile
Robert E Ergun
Univeristy of Colorado, Univeristy of Colorado
Author Profile
Kucharek Harald
University of New Hampshire, University of New Hampshire
Author Profile
Lynn Bruce Wilson
NASA Goddard Space Flight Center, NASA Goddard Space Flight Center
Author Profile
Li-Jen Chen
NASA Goddard Space Flight Center, NASA Goddard Space Flight Center
Author Profile
Katherine Amanda Goodrich
University of California, Berkeley, University of California, Berkeley
Author Profile
Drew L. Turner
The Johns Hopkins University Applied Physics Laboratory, The Johns Hopkins University Applied Physics Laboratory
Author Profile
Imogen Gingell
School of Physics and Astronomy, University of Southampton, School of Physics and Astronomy, University of Southampton
Author Profile
Hadi Madanian
Southwest Research Institute, Southwest Research Institute
Author Profile
Daniel J Gershman
NASA Goddard Space Flight Center, NASA Goddard Space Flight Center
Author Profile
Robert J. Strangeway
University of California Los Angeles, University of California Los Angeles
Author Profile


Shock waves are common in the heliosphere and beyond. The collisionless nature of most astrophysical plasmas allows for the energy processed by shocks to be partitioned amongst particle sub-populations and electromagnetic fields via physical mechanisms that are not well understood. The electrostatic potential across such shocks is frame dependent. In a frame where the incident bulk velocity is parallel to the magnetic field, the deHoffmann-Teller frame, the potential is linked directly to the ambipolar electric field established by the electron pressure gradient. Thus measuring and understanding this potential solves the electron partition problem, and gives insight into other competing shock processes. Integrating measured electric fields is space is problematic since the measurements can have offsets that change with plasma conditions. The offsets, once integrated, can be as large or larger than the shock potential. Here we exploit the high-quality field and plasma measurements from NASA's Magnetospheric Multiscale mission to attempt this calculation. We investigate recent adaptations of the deHoffmann-Teller frame transformation to include time variability, and conclude that in practise these face difficulties inherent in the 3D time-dependent nature of real shocks by comparison to 1D simulations. Potential estimates based on electron fluid and kinetic analyses provide the most robust measures of the deHoffmann-Teller potential, but with some care direct integration of the electric fields can be made to agree. These results suggest that it will be difficult to independently assess the role of other processes, such as scattering by shock turbulence, in accounting for the electron heating.