English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A charged particle traversing a plasma loses its energy to both plasmaelectrons and ions. We compute the energy partition, the fractions $E_e/E_0$and $E_\smI/E_0$ of the initial energy $E_0$ of this `impurity particle' thatare deposited into the electrons and ions when it has slowed down into anequilibrium distribution that we shall determine. We use a well-definedFokker-Planck equation for the phase space distribution of the charged impurityparticles in a weakly to moderately coupled plasma. The Fokker-Planck equationholds to first sub-leading order in the dimensionless plasma coupling constant,which means we compute to order $n\ln n$ (leading) and $n$ (sub-leading) in theplasma density $n$. Previously, the order $n$ terms had been estimated, notcalculated. Since the charged particle does not come to rest, the energy lossobtained by an integration of a $dE/dx$ has an ambiguity of order of the plasmatemperature. Our Fokker-Planck formulation provides an unambiguous, precisedefinition of the energy fractions. For equal electron and ion temperatures, wefind that our precise results agree well with a fit obtained by Fraley,Linnebur, Mason, and Morse. The case with differing electron and iontemperatures, a case of great importance for nuclear fusion, will beinvestigated in detail in the present paper. The energy partitions for thisgeneral case, partitions that have not been obtained before, will be presented.We find that now the proper solution of the Fokker-Planck equation yields aquasi-static equilibrium distribution to which fast particles relax that hasneither the electron nor the ion temperature. This "schizophrenic" finalensemble of slowed particles gives a new mechanism to bring the electron andion temperatures together. The rate at which this new mechanism brings theelectrons and ions in the plasma into thermal equilibrium will be computed.

Charged Particle Motion in a Plasma: Electron-Ion Energy Partition