A new conductivity for lower-hybrid-wave heated plasmas is derived. This in
duced conductivity shows a nonlinear behavior in the presence of an electri
c field and can represent the plasma as an active element. The role of runa
way electrons produced is important on this nonlinear conductivity. The new
expression may be important for radio frequency current drive ramp-up and
current drive efficiency by the lower-hybrid wave. (C) 2001 American Instit
ute of Physics.