A thermodynamical analysis of rf current drive with fast electrons
The problem of rf current drive (CD) by pushing fast electrons with highparallelphasevelocity waves, such as lowerhybrid (LH) or electroncyclotron (EC) waves, is revisited using the first and second laws, the former to retrieve the wellknown onedimensional (1D) steadystate CD efficiency, and the latter to calculate a lower bound for the rate of entropy production when approaching steady state. The laws of thermodynamics are written in a form that explicitly takes care of frictional dissipation and are thus applied to a population of fast electrons evolving under the influence of a dc electric field, rf waves, and collisions while in contact with a thermal, Maxwellian reservoir with a welldefined temperature. Besides the laws of macroscopic thermodynamics, there is recourse to basic elements of kinetic theory only, being assumed a residual dc electric field and a strong rf drive, capable of sustaining in the resonant region, where waves interact with electrons, a raised fastelectron tail distribution, which becomes an essentially flat plateau in the case of the 1D theory for LHCD. Within the 1D model, particularly suited for LHCD as it solely retains fastelectron dynamics in velocity space parallel to the ambient magnetic field, an H theorem for rf CD ismore »
 Authors:

^{[1]}
 Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049001 Lisboa (Portugal)
 Publication Date:
 OSTI Identifier:
 22490059
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 8; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COLLISIONS; ECR CURRENT DRIVE; ELECTRIC FIELDS; ELECTRONS; EQUATIONS; H THEOREM; LOWER HYBRID CURRENT DRIVE; LOWER HYBRID HEATING; MAGNETIC FIELDS; ONEDIMENSIONAL CALCULATIONS; PERFORMANCE; PHASE VELOCITY; RF SYSTEMS; THERMODYNAMICS