Momentum diffusion in current drive by electron plasma waves

Seppo Karttunen, Timo Pättikangas, Rainer Salomaa

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)

Abstract

Fast electron acceleration and velocity diffusion are investigated in wavepackets formed by large-amplitude waves with relativistic phase velocities. In tokamaks, such waves are generated, e.g. in current drive by free-electron lasers where large-amplitude electron plasma waves or lower hybrid waves are generated. At small field intensities, the velocity diffusion in wavepackets with Gaussian-like envelopes is found to be well described by the quasilinear approximation. At large field intensities, trapping effects become important, and deviations from quasilinear diffusion are found. It is demonstrated that these deviations may have a significant effect on the velocity distribution of the electrons. A wave-induced runaway-like phenomenon of relativistic electrons is discussed.
Original languageEnglish
Pages (from-to)657-671
Number of pages15
JournalPlasma Physics and Controlled Fusion
Volume36
Issue number4
DOIs
Publication statusPublished - 1994
MoE publication typeA1 Journal article-refereed

Fingerprint

Plasma waves
plasma waves
electron plasma
Momentum
momentum
Electrons
relativistic velocity
deviation
electron acceleration
Phase velocity
Free electron lasers
Velocity distribution
phase velocity
free electron lasers
electrons
envelopes
velocity distribution
trapping
approximation

Cite this

Karttunen, Seppo ; Pättikangas, Timo ; Salomaa, Rainer. / Momentum diffusion in current drive by electron plasma waves. In: Plasma Physics and Controlled Fusion. 1994 ; Vol. 36, No. 4. pp. 657-671.
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Momentum diffusion in current drive by electron plasma waves. / Karttunen, Seppo; Pättikangas, Timo; Salomaa, Rainer.

In: Plasma Physics and Controlled Fusion, Vol. 36, No. 4, 1994, p. 657-671.

Research output: Contribution to journalArticleScientificpeer-review

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T1 - Momentum diffusion in current drive by electron plasma waves

AU - Karttunen, Seppo

AU - Pättikangas, Timo

AU - Salomaa, Rainer

PY - 1994

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N2 - Fast electron acceleration and velocity diffusion are investigated in wavepackets formed by large-amplitude waves with relativistic phase velocities. In tokamaks, such waves are generated, e.g. in current drive by free-electron lasers where large-amplitude electron plasma waves or lower hybrid waves are generated. At small field intensities, the velocity diffusion in wavepackets with Gaussian-like envelopes is found to be well described by the quasilinear approximation. At large field intensities, trapping effects become important, and deviations from quasilinear diffusion are found. It is demonstrated that these deviations may have a significant effect on the velocity distribution of the electrons. A wave-induced runaway-like phenomenon of relativistic electrons is discussed.

AB - Fast electron acceleration and velocity diffusion are investigated in wavepackets formed by large-amplitude waves with relativistic phase velocities. In tokamaks, such waves are generated, e.g. in current drive by free-electron lasers where large-amplitude electron plasma waves or lower hybrid waves are generated. At small field intensities, the velocity diffusion in wavepackets with Gaussian-like envelopes is found to be well described by the quasilinear approximation. At large field intensities, trapping effects become important, and deviations from quasilinear diffusion are found. It is demonstrated that these deviations may have a significant effect on the velocity distribution of the electrons. A wave-induced runaway-like phenomenon of relativistic electrons is discussed.

U2 - 10.1088/0741-3335/36/4/007

DO - 10.1088/0741-3335/36/4/007

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