We studied the electron beam generation in high-current diode with various cathode shapes and the beam propagation through vacuum or plasma delivered to metallic drift tube. The combined effect of external longitudinal and self-consistent azimuthal magnetic fields with the accelerating electric field is discussed. We are interested in obtaining the diode efficiency and beam characteristic in stationary state.

Scattered emission from the laser plasma created in shell target heating experiments using the Delfin-1 laser has been studied. It is shown that the ω0 spherical harmonics can be used to determine both the plasma temperature in the nc/4 region and also the plasma flow through this region.

It has been recently suggested (Hora & Miley 1984) that in the cannonball scheme of laser compression the pellet may be considered to be compressed by the ‘brute force’ of the radiation pressure. For such a radiation-driven compression, this paper applies an energy balance method to give an equation fixing the radius compression ratio κ which is a key parameter for such intense compressions. A shock model is used to yield specific results. For a square-pulse driving power compressing a spherical pellet with a specific heat ratio of 5/3, a density compression ratio Γ of 27 is computed. Double (stepped) pulsing with linearly rising power enhances Γ to 1750. The value of Γ is not dependent on the absolute magnitude of the piston power, as long as this is large enough. Further enhancement of compression by multiple (stepped) pulsing becomes obvious. The enhanced compression increases the energy gain factor G for a 100 μm DT pellet driven by radiation power of 1016 W from 6 for a square pulse power with 0·5 MJ absorbed energy to 90 for a double (stepped) linearly rising pulse with absorbed energy of 0·4 MJ assuming perfect coupling efficiency.

A nonlinear relaxation is observed when an electron beam interacts with plasma in an external magnetic field. An acceleration of electrons to energies which are more than twice that of the initial beam energy is observed. The acceleration mechanism is connected with the modulation instability of the plasma waves which is excited when the beam relaxes.

The evolution of rf-accelerator technology toward high-power, high-current, lowemittance beams produces an ever-increasing demand for efficient, very high power microwave power sources. The present klystron technology has performed very well but is not expected to produce reliable gigawatt peak-power units in the 1- to 10-GHz regime. Further major advancements must involve other types of sources. The reflexing-electron class of sources can produce microwave powers at the gigawatt level and has demonstrated operation from 800-MHz to 40-GHz. The pulse length appears to be limited by diode closure, and reflexing-electron devices have been operated in a repetitively pulsed mode. A design is presented for a reflexing electron microwave amplifier that is frequency and phase locked. In this design, the generated microwave power can be efficiently coupled to one or several accelerator loads. Frequency and phase-locking capability may permit parallel-source operation for higher power. The low-frequency (500-MHz to 10-GHz) operation at very high power required by present and proposed microwave particle accelerators makes an amplifier, based on reflexing electron phenomena, a candidate for the development of new accelerator power sources.

Plasma heating by short laser pulses is investigated theoretically. Gain coefficients of 3… 4 cm−1 at the Balmer α transition in carbon could be obtained. The theoretical results agree with the corresponding experimental findings.