High power heating and current drive (H&CD) facilities are required to fulf
il a number of functions in Next Step tokamaks such as ITER and in power pl
ants. The main functions of the ITER H&CD systems are: start-up assist; H-m
ode access; heating to ignition; supplementary heating for driven-burn and
for controlled plasma shut-down; current drive for extended burn and access
to steady-state regimes; performance optimisation, control of plasma insta
bilities and making the plasma rotate. This paper reviews recent progress w
ith H&CD systems, which has largely come about in response to the needs of
ITER [1-3]. We survey how the designs have been influenced by physics requi
rements and technical constraints (such as reliable c.w. operation with mod
ular integrated port plug designs), and emphasise key outstanding issues. T
he four main candidate systems are: electron and ion cyclotron resonance fr
equency, lower hybrid, and neutral beam heating. These all have their own p
hysics and technology advantages, and disadvantages, and their components a
re at various stages of development. (C) 1999 UKAEA Fusion. Published by El
sevier Science S.A. All rights reserved.