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Title: On neutral-beam injection counter to the plasma current

Abstract

It is well known that when neutral beams inject ions into trapped orbits in a tokamak, the transfer of momentum between the beam and the plasma occurs through the torque exerted by a radial return current. It is shown that this implies that the angular momentum transferred to the plasma can be larger than the angular momentum of the beam, if the injection is in the opposite direction to the plasma current and the beam ions suffer orbit losses. On the Mega-Ampere Spherical Tokamak (MAST) [R. J. Akers, J. W. Ahn, G. Y. Antar, L. C. Appel, D. Applegate, C. Brickley et al., Plasma Phys. Controlled Fusion 45, A175 (2003)], this results in up to 30% larger momentum deposition with counterinjection than with co-injection, with substantially increased plasma rotation as a result. It is also shown that heating of the plasma (most probably of the ions) can occur even when the beam ions are lost before they have had time to slow down in the plasma. This is the dominant heating mechanism in the outer 40% of the MAST plasma during counterinjection.

Authors:
; ;  [1];  [2]
  1. EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom)
  2. (France)
Publication Date:
OSTI Identifier:
20782344
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 12; Journal Issue: 11; Other Information: DOI: 10.1063/1.2121287; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANGULAR MOMENTUM; ANGULAR MOMENTUM TRANSFER; BEAM INJECTION HEATING; CHARGED-PARTICLE TRANSPORT; ELECTRIC CURRENTS; IONS; MAST TOKAMAK; PARTICLE LOSSES; PLASMA; PLASMA BEAM INJECTION; PLASMA CONFINEMENT; ROTATION; TRAPPING

Citation Formats

Helander, P., Akers, R.J., Eriksson, L.-G., and Association EURATOM-CEA, CEA/DSM/DRFC, CEA Cadarache, F-13108 St. Paul lez Durance. On neutral-beam injection counter to the plasma current. United States: N. p., 2005. Web. doi:10.1063/1.2121287.
Helander, P., Akers, R.J., Eriksson, L.-G., & Association EURATOM-CEA, CEA/DSM/DRFC, CEA Cadarache, F-13108 St. Paul lez Durance. On neutral-beam injection counter to the plasma current. United States. doi:10.1063/1.2121287.
Helander, P., Akers, R.J., Eriksson, L.-G., and Association EURATOM-CEA, CEA/DSM/DRFC, CEA Cadarache, F-13108 St. Paul lez Durance. Tue . "On neutral-beam injection counter to the plasma current". United States. doi:10.1063/1.2121287.
@article{osti_20782344,
title = {On neutral-beam injection counter to the plasma current},
author = {Helander, P. and Akers, R.J. and Eriksson, L.-G. and Association EURATOM-CEA, CEA/DSM/DRFC, CEA Cadarache, F-13108 St. Paul lez Durance},
abstractNote = {It is well known that when neutral beams inject ions into trapped orbits in a tokamak, the transfer of momentum between the beam and the plasma occurs through the torque exerted by a radial return current. It is shown that this implies that the angular momentum transferred to the plasma can be larger than the angular momentum of the beam, if the injection is in the opposite direction to the plasma current and the beam ions suffer orbit losses. On the Mega-Ampere Spherical Tokamak (MAST) [R. J. Akers, J. W. Ahn, G. Y. Antar, L. C. Appel, D. Applegate, C. Brickley et al., Plasma Phys. Controlled Fusion 45, A175 (2003)], this results in up to 30% larger momentum deposition with counterinjection than with co-injection, with substantially increased plasma rotation as a result. It is also shown that heating of the plasma (most probably of the ions) can occur even when the beam ions are lost before they have had time to slow down in the plasma. This is the dominant heating mechanism in the outer 40% of the MAST plasma during counterinjection.},
doi = {10.1063/1.2121287},
journal = {Physics of Plasmas},
number = 11,
volume = 12,
place = {United States},
year = {Tue Nov 15 00:00:00 EST 2005},
month = {Tue Nov 15 00:00:00 EST 2005}
}