The Tokamak Physics Experiment is designed to develop the scientific basis for a compact and continuously operating tokamak fusion reactor. It is based on an emerging class of tokamak operating modes, characterized by beta limits well in excess of the Troyon limit, confinement scaling well in excess of H-mode, and bootstrap current fractions approaching unity. Such modes are attainable through the use of advanced, steady state plasma controls including strong shaping, current profile control, and active particle recycling control. Key design features of the TPX are superconducting toroidal and poloidal field coils; actively-cooled plasma-facing components; a flexible heating and current drive system; and a spacious divertor for flexibility. Substantial deuterium plasma operation is made possible with an in-vessel remote maintenance system, a lowactivation titanium vacuum vessel, and shielding of ex-vessel components. The facility will be constructed as a national project with substantial participation by U.S. industry. Operation will begin with first plasma in the year 2000.

A major probiem area in the study of the feasibility of fusion reactors is the attainment of hot dense plasma for experimental study and the determination of a heating scheme to reach ignition conditions in a reactor. Adiabatic compression in minor and major radius of •Tokamak configuration plasmas was proposed as a means of reaching this end. The Adiabatic Toroidal Compressor (ATC) was built at the Princeton Plasma Physics Laboratory to determine experimentally the feasibility of this technique. This paper de-s~ribes the engineering features of this machine. Preliminary results lndlcate that compression heating is a possible method of assisting reaching fusion i.gni ti.on temperatures.

In this article a class AB single‐ended power amplifier with 30‐512 MHz frequency band and 100 W saturated output power has been designed and implemented using a GaN transistor. The measured compressed gain is 19 ± 1 dB, the average PAE is 61% and the return loss is always better than −7.5 dB.

No abstract