Evidence for Electron Landau Damping in Space Plasma Turbulence. (arXiv:1902.05785v1 [physics.space-ph])
<a href="http://arxiv.org/find/physics/1/au:+Chen_C/0/1/0/all/0/1">C. H. K. Chen</a>, <a href="http://arxiv.org/find/physics/1/au:+Klein_K/0/1/0/all/0/1">K. G. Klein</a>, <a href="http://arxiv.org/find/physics/1/au:+Howes_G/0/1/0/all/0/1">G. G. Howes</a>
How turbulent energy is dissipated in weakly collisional space and
astrophysical plasmas is a major open question. Here, we present the
application of a field-particle correlation technique to directly measure the
transfer of energy between the turbulent electromagnetic field and electrons in
the Earth’s magnetosheath, the region of solar wind downstream of the Earth’s
bow shock. The measurement of the secular energy transfer from the parallel
electric field as a function of electron velocity shows a signature consistent
with Landau damping. This signature is coherent over time, close to the
predicted resonant velocity, similar to that seen in kinetic Alfv’en
turbulence simulations, and disappears under phase randomisation. This suggests
that electron Landau damping could play a significant role in turbulent plasma
heating, and that the technique is a valuable tool for determining the particle
energisation processes operating in space and astrophysical plasmas.
How turbulent energy is dissipated in weakly collisional space and
astrophysical plasmas is a major open question. Here, we present the
application of a field-particle correlation technique to directly measure the
transfer of energy between the turbulent electromagnetic field and electrons in
the Earth’s magnetosheath, the region of solar wind downstream of the Earth’s
bow shock. The measurement of the secular energy transfer from the parallel
electric field as a function of electron velocity shows a signature consistent
with Landau damping. This signature is coherent over time, close to the
predicted resonant velocity, similar to that seen in kinetic Alfv’en
turbulence simulations, and disappears under phase randomisation. This suggests
that electron Landau damping could play a significant role in turbulent plasma
heating, and that the technique is a valuable tool for determining the particle
energisation processes operating in space and astrophysical plasmas.
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