Design and test of a large plasma torch for environmental recycling

A 2.5-inch inductive plasma torch has been tested with up to 600 kW rf power and with argon, nitrogen, and oxygen gases. A complete power balance is obtained from electrical, thermal, and radiation measurements. These data indicate that torch efficiencies of up to 30% are obtained with molecular gases, while efficiencies around 15% are obtained with argon. The efficiencies obtained with molecular gases almost triple earlier torch efficiencies and confirm substantially the predictions of a torch model developed during a previous CRADA. Torch efficiencies of up to 50% could be obtained in future tests with an improved rf power supply, with steam gas, and with larger torch dimensions. Future applications of the Plasma Energy Recycle and Conversion (PERC) process could include the high explosives of DOE`s nuclear weapons, chemical and biological remediation, and the treatment and volume reduction of radioactive mixed waste

Onset and saturation of ion heating by odd-parity rotating-magnetic-fields in a field-reversed configuration

Heating of figure-8 ions by odd-parity rotating magnetic fields ($RMF_o$) applied to an elongated field-reversed configuration (FRC) is investigated. The largest energy gain occurs at resonances ($s \equiv \omega_R/ \omega$) of the $RMF_o$ frequency, $\omega_R$, with the figure-8 orbital frequency, $\omega$, and is proportional to $s^2$ for $s-even$ resonances and to $s$ for $s-odd$ resonances. The threshold for the transition from regular to stochastic orbits explains both the onset and saturation of heating. The FRC magnetic geometry lowers the threshold for heating below that in the tokamak by an order of magnitude.Comment: 4 page, 3 figure

Measurement of loss of DT fusion products using scintillator detectors in TFTR

A poloidal array of MeV ion loss probes previously used to measure DD fusion product loss has been upgraded to measure the loss of alpha particles from DT plasmas in TFTR. The following improvements to the system have been made in preparation for the use of tritium in TFTR: (1) relocation of detectors to a neutronshielded enclosure in the basement to reduce neutron-induced background signals; (2) replacement of ZnS:Cu (P31) scintillators in the probes with the Y{sub 3}Al{sub 5}0{sub 12}:Ce(P46) variety to minimize damage and assure linearity at the fluxes anticipated from DT plasmas; and (3) shielding of the fiber optic bundles which carry the fight from the probes to the detectors to reduce neutron- and gamma-induced light within them. In addition to the above preparations, the probes have been absolutely calibrated for alpha particles by using the Van de Graaf accelerator at Los Alamos National Laboratory. Alpha particle losses from DT plasmas have been observed, and losses at the detector 901 below the midplane are consistent with first orbit loss

Recent FRC translation experiments on FRX-C/T

Since the last CT Symposium, several accomplishments have been realized from the FRC translation studies on the FRX-C/T device: (1) FRCs have been launched into, and trapped in, a dc magnetic guide field region without the use of any pulsed ''gate'' coils; (2) detailed studies of translation dynamics have been performed which are consistent with energy conservation, adiabatic compression theory, and 2-D MHD simulations; (3) the confinement properties of translated FRC has been evaluated; (4) translation through either puff or static deuterium gas fill has been demonstrated; (5) higher density (n less than or equal to 4 x 10/sup 15/ cm/sup -3/) FRCs have been translated over 10-m lengths; (6) the n = 2 rotational instability has been stabilized by FRC translation into a weak helical quadrupole field

Magnetic fusion with high energy self-colliding ion beams

Self-consistent equilibria are obtained for high beta plasma where almost all of the ions are ene with a gyroradius of the order of the plasma scale length. Magnetohydrodynamics would not apply to such a plasma. Recent experiments with tokamaks suggest that it would be insensitive to microinstabilities. Several methods are described for creating the plasma with intense neutralized ion beams

Preliminary Langmuir probe results on the CTX gun experiment

Preliminary results obtained with a double Langmuir probe in the Compact Toroid experiment facility confirm the existence of a gun plasma of n approx. 5 x 10/sup 14/ cm/sup -3/ and T approx. 10 eV lasting for approx. 250 to 400 ..mu..s, which is consistent with interferometry and Thomson scattering data. The probe current characteristics as a function of voltage suggest non-Maxwellian features of the particles distribution functions