No abstract available

[en] JET utilises RF waves in the 25-55 MHz range for additional plasma heating. Presently, 3 antennae are in operation each delivering up to 3 MW of RF power to the plasma. Various parts made from 97% pure alumina are employed for electrical insulation and for separation of the evacuated part from the pressurised part of the system. With only little neutron production so far, all ceramics worked satisfactorily. (author)

[en] This chapter considers the optimization of the laser energy required for ionizing large pellets, particularly the application of multi-phase heating. Topics covered include wavelength selection and magnetic field effects on laser pellet plasmas. Pellet irradiation and pellet plasma expension are examined. It is concluded that the production of fully ionized pellet plasmas with a properly timed sequence of laser pulses is possible with reasonable laser energies; recombination and charge exchange processes which may impair the effectiveness of the method may be overcome by additional heating of the laser pellet plasma produced; and methods are available for reducing or eliminating the initial drift losses inherent in certain magnetic field configurations. Includes 2 photos and 1 drawing

[en] A simple and reliable system has been developed for the production of hydrogen plasmas by irradiating freely falling pellets with a high power laser. The pellet source is able to deliver pellets of variable size and very low scattering. The overall probability for hiting a pellet with the laser is about 70%. Plasmas have been produced and investigated. Preliminary results of these investigations are presented

No abstract available

[en] Freely falling deuterium pellets are irradiated with a high power Nd laser and ionized. The influence of the following para,meters on plasma production are investigated: laser energy of prepulse and main pulse, pulse separation, laser beam diameter at the pellet site and irradiation from one and two directions. Under optimum conditions for all these parameters almost 100 per cent ionization of the pellet is achieved. Approximately 30 per cent of the laser energy is measured as ion kinetic energy of the plasma. The number of electrons was determined by holographic interferometry, the number and energy of ions are measured with 12 Faraday cups. The laser0energy balance was achieved with various diodes, calorimeters and an integrating sphere around the pellet site. (author)

No abstract available

[en] An account is given of the proposals for lower hybrid current drive in ASDEX tokamak. (U.K.)

[en] The physics aspects of tokamak plasma heating with ion-cyclotron waves are reviewed in the light of initial experiments in JET. The power coupled to the plasma has reached 5.5 MW. Central temperatures of both the ions and electrons have more than doubled. Peak values reached 5 keV. The data are well represented by a law which is stated. The power deposition appears highly localized in the vicinity of the cyclotron resonance and preliminary experiments on the effect of local deposition on confinement have been performed. The best heating conditions are obtained with central power deposition or with a slightly outboard shift for best ion heating. These optimum conditions also correspond to large sawtooth relaxation of the temperature of the plasma core. (author)

[en] A high-power Nd : glass laser beam was focused on freely falling deuterium ice pellets. It was demonstrated that this method allows reliable and reproducible production of an isolated deuterium plasma cloud suitable for filling a plasma machine. The plasma with a total ion number of (1--2) x 10¹⁷ expands quite uniformly at a velocity of (1--3) x 10⁷ cm/s. However, the pellet is not completely ionized, which is in accordance with theoretical predictions. The greater portion of the pellet disintegrates after the laser shot and expands with a velocity of approximately 1 x 10⁶ cm/s