Ion cyclotron and lower hybrid arrays applicable to current drive in fusion reactors

Abstract

This paper presents concepts for Ion Cyclotron and Lower Hybrid Current Drive arrays applicable to fusion reactors and based on periodically loaded line power division. It is shown that, in large arrays, such as the ones proposed for fusion reactor applications, these schemes can offer, in principle, a number of practical advantages, compared with currently adopted ones, such as in-blanket operation at significantly reduced power density, lay out suitable for water cooling, single ended or balanced power feed, simple and load independent impedance matching In addition, a remote and accurate real time measurement of the complex impedance of all array elements as well as detection, location, and measurement of the complex admittance of a single arc occurring anywhere in the structure is possible.

Potential of ion cyclotron resonance frequency current drive via fast waves in DEMO

“…The second possibility is to take advantage of the larger DEMO size and design a wider antenna, which by definition excites lower k ‖ modes. Finally, there is an ongoing discussion of composing the ICRF antenna out of an array of toroidally distributed straps, which should allow operation at practically single value k ‖ in the antenna spectrum [47,48]. Note that lowering k ‖ will also improve coupling of the ICRF power to the plasma since it reduces the width of the evanescence layer in front of the antenna.…”