RF Heating Systems Research Articles

Radio frequency heating and current drive - status and prospects for the next step

Additional heating is a necessary requirement on all tokamaks and stellarators. All the major devices are now equipped with large additional RF heating systems and the actual data base both on the physics aspects and on the technical aspects is large and still expanding [1,2]. Radio Frequency techniques in the Ion Cyclotron (ICR), Lower Hybrid (LH) and Electron Cyclotron (ECR) range of frequency have proved to be very effective for one or more of their potential applications: heating, profile control, bulk current drive, non-inductive current ramp up and plasma initiation and are planned to be used on the Next Step facility. Although other RF methods are being developed, such as Ion Bernstein wave heating and current drive and Alfvén wave heating, we will restrict the discussion to the most promising and well documented methods. The corresponding main results to date and some of the relevant physics basis will be discussed first. The technical status of coupling structures, transmission lines and generators will then be given. RF techniques cover a large domain both in the physics and in the technical aspects, and consequently only highlights of the different methods will briefly be indicated.

Plasma Instrumentation for Fusion Power Reactor Control

Feedback control will be implemented in fusion power reactors to guard against unpredicted behavior of the plant and to assure desirable operation. In this study, plasma state feedback requirements for plasma control by systems strongly coupled to the plasma (magnet sets, RF, and neutral beam heating systems, and refueling systems) are estimated. Generic considerations regarding the impact of the power reactor environment on plasma instrumentation are outlined. Solutions are proposed to minimize the impact of the power reactor environment on plasma instrumentation. Key plasma diagnostics are evaluated with respect to their potential for upgrade and implementation as power reactor instruments.

Ceramics for fusion devices

Ceramics are required for a number of applications in fusion devices, among the most critical of which are magnetic coil insulators, windows for RF heating systems, and structural uses. Radiation effects dominate consideration of candidate materials, although good preirradiation properties are a requisite. Materials and components can be optimized by careful control of chemical and micro structural content, and application of brittle material design and testing techniques. Future directions for research and development should include further extension of the data base in the areas of electrical, structural, and thermal properties; establishment of a fission neutron/fusion neutron correlation including transmutation gas effects; and development of new materials tailored to meet the specific needs of fusion reactors.

Development of the Industrial Use of Dielectric Heating in the United Kingdom

In the United Kingdom, RF heating systems have become well established in many industries since their first introduction over forty years ago, Today RF probably accounts for 90% of all dielectric heating applications. The introduction of microwave heating was a later development and, in contrast to RF, applications arc only just becoming established. In the present state of world economy, the need for the wise selection of possible new applications has never been greater, and can be the key to survival and ultimate commercial success for industrial heating equipment suppliers. This paper highlights the development of industrial application of dielectric heating in the UK for RF wood glueing, plastics, preheating, and welding, biscuit baking, textile drying, adhesive and paper drying, microwave preheating and vulcanisation of rubber, microwave tempering of meat and other food processing applications.