Lower hybrid current drive experiments on the TdeV tokamak

Current drive experiments have been performed on TdeV over a wide range of parameters. It is found that the current drive efficiency {eta} does not scale with {ital N}{sub {parallel}} as expected from simple theory. Simulations with the ACCOME code suggest that the reduced efficiency at low {ital N}{sub {parallel}} values is mostly due to a large toroidal upshift in the LH wave spectrum. The loss of suprathermal electrons to the divertor plates was monitored during CD experiments. The power loss increases with decreasing {ital N}{sub {parallel}} values and can be reach up to 15{percent} of the injected rf power in low density plasmas. {copyright} {ital 1996 American Institute of Physics.}