RF heating experiments in CHS and RF development for LHD

The Lame Helical Device, LHD, is in its final construction phase. It is a 1=2, m=10 Heliotron/Torsatron type helical system with a major radius of 4 m. The compact helical system, CHS, is a 1=2, m=8 helical system of the same type with a major radius of 1m. CHS has been used for supporting experiments to clarify physics issues of helical systems and to examine the key ideas which will be applied to LHD. This paper summarizes the experimental results of those supporting experiments in CHS and how this knowledge is incorporated in the design of RF heating in LHD. ICRF Heating results in CHS by use of loop antennas are described in section II. The results of using a Nagoya type-III coil is described in Section III. Two types of antennas used in the initial phase of the LHD ICRF Heating: a loop antenna designed for steady state heating and a folded wave guide antenna designed for EBW, are described in section IV