On neutral-beam injection counter to the plasma current

Journal Article · Tue Nov 15 04:00:00 EST 2005 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2121287· OSTI ID:20782344

Helander, P; Akers, R J; Eriksson, L -G ^[1]

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1. EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom)

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.

• OSTI ID: 20782344
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 11 Vol. 12; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

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