Ion-beam excitation of liquid argon

The scintillation light of liquid argon has been recorded wavelength and time resolved with very good statistics in a wavelength interval ranging from 118 nm through 970 nm. Three different ion beams, protons, sulfur ions and gold ions, were used to excite liquid argon. Only minor differences were observed in the wavelength-spectra obtained with the different incident particles. Light emission in the wavelength range of the third excimer continuum was found to be strongly suppressed in the liquid phase. In time-resolved measurements, the time structure of the scintillation light can be directly attributed to wavelength in our studies, as no wavelength shifter has been used. These measurements confirm that the singlet-to-triplet intensity ratio in the second excimer continuum range is a useful parameter for particle discrimination, which can also be employed in wavelength-integrated measurements as long as the sensitivity of the detector system does not rise steeply for wavelengths longer than 190 nm. Using our values for the singlet-to-triplet ratio down to low energies deposited a discrimination threshold between incident protons and sulfur ions as low as ∼2.5 keV seems possible, which represents the principle limit for the discrimination of these two species in liquid argon

Radio-Frequency Energy in Fusion Power Generation

The history of radio-frequency (rf) energy in fusion experiments is reviewed, and the status of current efforts is described. Potential applications to tasks other than plasma heating are described, as are the research and development needs of rf energy technology

Effects of global field errors on ELMO Bumpy Torus

The plasma sensitivity to magnetic field error effects has been tested experimentally using externally introduced global field errors in the ELMO Bumpy Torus (EBT). A critical field (delta B/sub r//B)/sub cr/ approximately 0.6-1 x 10/sup -3/ was observed, below which the plasma is essentially free from convective cells, toroidal currents, and instabilities. The observed critical value is comparable to a neoclassical critical field error (delta B/sub r//B)/sub cr/ approximately equal to rho/R, the ratio of the ion Larmor radius to the major radius of the torus