The advent of high-peak-power pulsed microwave sources opens possibilities for novel current-drive schemes in tokamaks. Four such schemes are considered: accelerating phase-space buckets, overlap of relativistic electron-cyclotron harmonics, beat-wave generation and burnthrough of intense lower-hybrid waves. These schemes are found to offer one or more of the following advantages over their continuous-power counterparts: improved efficiency, improved access to the core plasma, and precise control of the deposition profile. 17 refs.

The complete set of eigenvalues and eigenmodes is elaborated for a random walk on a two-dimensional N )times) N square lattice torus with one trap site. The eigenvalue closest to unity is found to have an asymptotic expansion in N; the leading behavior is lambda )approximately) 1 )minus) ..pi.. (2N/sup 2/ log N) )plus) O(N log N)/sup )minus/2). In general, the eigenvalues and eigenmodes for this problem are constructed from those for a random walk on the same lattice containing no trap. The degeneracy of the latter eigenmodes is a prominent feature of this construction, and a formula is derived for this degeneracy. 9 refs., 2 figs

Recent advances in High Average Power (HAP) solid state lasers and the development of new concept lasers with the potential of ultra- high average power output have put increasing demands on the transparency of optical window materials. To gain a better understanding of the current status of window materials and to direct research toward more nearly transparent materials, we have constructed an optical characterization facility with the purpose of making quantitative optical loss measurements in the sensitivity range of 10/sup /minus/3/ to 10/sup /minus/6/ cm/sup /minus/1/. The cornerstone of this facility is a scanning optical lossmeter in which loss is determined by comparing the decay time of an optical cavity with and without a transparent solid present. The lossmeter has been successfully applied to measurements of the optical loss of witness samples of highly transparent fused silica. A description of the lossmeter and a compilation of preliminary loss measurements are presented here. 3 refs.

A brief review of the phenomenology associated with the effort to produce and observe quark-gluon plasma in particle collisions is presented. E-735 has taken data during the 1987 Tevatron-Collider run at /square root/s = 1.8 TeV in pursuit of this goal. Results in the correlation of < p/sub t/ > with multiplicity for charged particles and p/sub t/ distributions for ..lambda../sup o/ and /bar Lambda//sup o/ are presented. 32 refs., 10 figs., 2 tabs.