The collimated electron jets ejected from cylindrical plasma are produced in particle-in-cell simulation under the applied longitudinal magnetostatic field and radial electrostatic field, which is a process that can be conveniently performed in a laboratory. We find that the applied magnetostatic field contributes significantly to the jet collimation, whereas the applied electrostatic field plays a vital role in the jet formation. The generation mechanism of collimated jets can be well understood through energy gain of the tagged electrons, and we conclude that the longitudinal momentum of the electrons is converted from the transverse momentum via the transverse-induced magnetic field. It has been found that the ejecting velocity of the jets is close to the speed of light when the applied electrostatic field reaches 3 × 1010 V/m. The present scheme may also give us an insight into the formation of astrophysical jets in celestial bodies.

We investigated several examples of ion beam targets that utilize the energy efficiency of direct drive while optimizing on the symmetry requirements. Heavy-ion beams of charge state Z ≥ 3 at 5–10 GeV have ≲15–20 m bending radii with 3.5-T fields. Beams like these could be used with targets involving direct drive. Control of asymmetries in direct-drive ion beam targets depends on control of the effects of residual target asymmetries after an appropriate illumination scheme has been adopted. In this paper, we outline results of our investigations into ion beam target concepts in which the effects of residual asymmetries are ameliorated. The beams are placed according to our axially symmetric Gaussian-quadrature illumination scheme (Mark 1986). The targets survive the effects of residual asymmetries in our recent 2-D hydrodynamic simulations. We also briefly discuss the additional positive effects of polarized DT fuel on ion beam targets.

The paper presents a cylindrical diode with a rod anode for repetitive pulsed intense X-ray sources. The diode uses a massive anode of diameter 1 cm, thus increasing the lifetime of the energy converter. The diode gap is preliminary filled with ions produced by cathode flare in a vacuum discharge, allowing electron beam pinching at a voltage of <200 kV. In the mode of pinching, the diode is an efficient source of high-power X rays. At a distance of 20 cm from the X-ray source, the radiation dose per pulse is 0.4 R at a peak power of 7 × 106 R/s. The full-width at half-maximum of the radiation pulse is 40 ns. The power in the diode is 1.8 GW at a beam current of 10 kA and exceeds the maximum power of the generator operating onto a matched load with constant resistance.

Particle beams with uniform and well-confined intensity distributions are desirable in some high power beam applications to prolong the target lifetime or to improve the beam utilization. Three kinds of elements had been proposed for the beam homogenizing, such as octupole, pole-piece magnet, and step-like nonlinear magnets. In this paper, the new type of elements called heteromorphic quadrupole and focus sextupole are proposed. The Gaussian-like multiparticle beam redistribution by the octupole, heteromophic quadrupole, step-like nonlinear magnets, and focus sextupole has been simulated by the POISSON and LEADS code. The best redistribution result is obtained by the focus sextupole, and one of the solutions of redistributing beam with big halo can be that of using the focus sextupole and the heteromorphic quadrupole.

By employing analytic solutions for the electromagnetic field at resonance absorption, first derived by Denisov, the total nonlinear force, in the plane of incidence has been evaluated. This 2-D force results in a conical type emission towards the vacuum and into the plasma which depends critically on the collision frequency and the density scale length. It is found that, for neodynium glass laser intensities of 1014 W/cm2, keV ions can be produced by nonlinear force acceleration. The analysis is limited by the following requirements: the dielectric constant varies linearly with distance, the angle of incidence is not too small and most importantly self consistent and transient wave processes occur at a later time and are neglected.

Physics of Inertial Fusion: Beam Plasma Interaction, Hydrodynamics, Hot Dense Matter, Stafano Atzeni and Jürgen Meyer-ter-Vehn, Clarendon Press, 2004, 458 pages, ISBN: 0198562640

This book has several remarkable highlights summarized on laser produced plasmas and particle beam driven fusion energy. In contrast to the usual books, the nuclear fusion reactions are presented with very detailed experience, including pycnonuclear reactions, spin polarization, and mentioning the 25 orders of magnitude less probable weak force pp-reaction than DT. There is a rather comprehensive collection of the conditions of confinement, spherical implosion, ignition burn, and gain. Hydrodynamics is based on a one fluid model, not Schlüter's space charge quasi-neutral two-fluid model nor the genuine two-fluid treatment. Hohlraum targets are covered and the fast ignition (FI) contains the forte of the authors' own achievements though the entire problems shown experimentally or theoretically (Mulser et al., 2004) are not discussed nor the new aspects on FI known before finishing the book (Hora, 2004). The 36 pages for the entire physics of (laser- and particle-) beam-target interaction are used to sketch at least the most important aspects.

We report on a new technique that we used to accurately time the velocity of a cluster beam. It involves deflecting particles away from their usual beam path by scattering with an ablation plume. We were able to time the occurrence of a C60 cluster beam to better than 0.2%. This technique was critical in recent light-force polarizabilities experiments.

A novel way for igniting small thermonuclear assemblies by inertial confinement is proposed, by replacing the positive mass of an imploding dense star with the negative mass in the reference frame of a rapidly rotating thermonuclear target. According to Einstein's general theory of relativity, this negative mass can be orders of magnitude larger than the positive mass density of a neutron star. This novel concept also replaces the Plutonium 239 “spark plugs” of large thermonuclear devices with a shell of natural uranium surrounding a target composed of DT or Li6D.

Unlike the ignition by a laser – or particle beam – induced spherical implosion, this configuration, similar to that of an imploding star is not only Rayleigh–Taylor stable, but it can be realized with intense relativistic electron or ion beams, with an energy of about 100 MJ, having a short range in the dense high Z natural uranium shell.

Four microseconds long Ar3+ beam with injection energy of 15 keV/u has been injected into the Digital Accelerator of the High-Energy Accelerator Research Organization. Beam production, transportation, and injection are described as well as machine properties. Results of a free running experiment under static magnetic field and longitudinal confinement and acceleration under a fast ramping magnetic field are presented in detail with a brief discussion on the beam lifetime.

The dynamics of an electron–ion plasma is studied when a mono-energetic relativistic electron beam penetrates the expanding plasma. Combined effects of thermal pressure and ambipolar electrostatic potential are considered for fully relativistic multi-fluids model where the quasi-neutrality assumption is used for a beam–plasma system. Relativistic effects are considered for both density and velocity of the beam fluid. Ion acceleration is depicted through a spike-like structure resulting from non-local charge separation and associated with the beak-down of quasi-neutrality. The beam initial speed is found to enhance the spike amplitude and change its position. Moreover, relativistic effects are particularly found significant for a non-thermal plasma.

When a heavy ion beam passes through a plasma in reactor chamber, it scatters some plasma electrons in the direction perpendicular to that of beam propagation. The presence of such electrons causes an instability to deflect the beam from the target pellet. The instability is analyzed by coupled equations for density and temperature for the electrons, and numerical results are given.

We present the results of the theoretical studies of the plasma heating in the flows which converge toward the axis of cylindrical cavity. We show that as a result of the shock wave reflection from the axis, the narrow hot filament is formed. This phenomenon is important for the interpretation of the dynamic processes in the electric discharges used for X-ray generation. We notice that the plasma parameters which can be of interest for inertial confinement fusion (ICF) can be reached in such the processes.

Radio frequency (RF) breakdown can result in pulse shortening and seriously degrade the stability and reliability of relativistic backward wave oscillators (RBWOs). This paper discusses the energy range of electrons causing breakdown traces in slow-wave structures (SWSs) through particle-in-cell (PIC) simulation, numerical calculation, and experimental verification. The PIC simulation and numerical calculation results reveal that the energy of the majority of the field-induced electrons bombarding the SWS surfaces after being accelerated is less than 120 keV. Furthermore, the micro appearances of the breakdown traces in SWSs and the witness targets bombarded directly by electrons of various energy levels have been analyzed. Scanning electron microscope (SEM) shows that the breakdown traces are featured with corrugated morphologies with a wide range and a shallow depth. A mass of craters emerge in the vicinity of the corrugated morphologies. These appearances are quite similar to destructive traces impacted directly by low-energy electrons (around 160 keV). Thus, it is confirmed that the breakdown traces result from the bombardment of low-energy electrons. Therefore, the breakdown mechanism of field-emitted electrons impacting on the structure surfaces in RBWOs has been further improved.

Models for the prediction of electron pedestal temperatures at the edge of type I ELMy H-mode plasmas are developed. These models are based on theory motivated concepts for pedestal width and pressure gradient. The pedestal pressure gradient is assumed to be limited by high n ballooning mode instabilities, where both the first and second stability limits are considered. The effect of the bootstrap current, which reduces the magnetic shear in the steep pressure gradient region at the edge of the H-mode plasma, can result in access to the second stability of ballooning mode. In these pedestal models, the magnetic shear and safety factor are calculated at one pedestal width away from separatrix. The predictions of these models are compared with the experimental electron pedestal temperatures for type I ELMy H-mode discharges obtained from the latest public version (version 3.2) in the International Tokamak Physics Activity Edge (ITPA) Pedestal Database.

To predict the gain in a lasing transition in ions of a laser-produced plasma, it is essential to calculate the amount of the reabsorption of radiation emitted in the transition from the lower laser level to the ground state. An important quantity influencing the reabsorption is the plasma geometry as resulting from the design of the laser and target system. Modeling a nonaxially symmetrical geometry of the plasma arising from a target irradiated by line-focused laser beams, we consider the plasma in the form of a longitudinally cut-out circular cylinder, with central angle ø, and the length of the plasma much larger than its transversal extension. Accounting for the effect of resonance line trapping via the escape probability approach, and taking the absorption profile in the line center approximation, an explicit formula for the photon escape probability depending on the radial and angular coordinates of an interior point in the plasma is derived. This function is averaged over the angular variable to obtain an only radially varying mean escape probability.

The possibility of heavy-ion beam-pumped ion lasers is demonstrated by observation of optical gain on the 476.5-nm Ar II 4p–4s ion laser transition in argon gas excited by 2.5–ns pulses of 110–MeV 32S ions with repetition rates up to 156 kHz. The particle energy per pulse was about 20 μJ. The projectiles were stopped in the target at pressures between 5 and 35 kPa. The beam from an argon ion probe laser operated at 476.5 nm was used to determine gain amplitude and time structure from a measured transient increase of the probe laser intensity when target excitation by the ion beam was present. The maximum gain observed was (0.5 ± 0.1) x 10-3 at a target gas pressure of 5 kPa. The optical gain observed in argon is consistent with calculations based upon an analysis of spectroscopic studies of rare gas targets excited by heavy-ion beams.

Temporal evolution of X-ray spectra of lead plasma produced by a CO2 laser pulse with energy of 100 J and a duration of 15 ns has been measured using a six-channel X-ray polychromator. The polychromator registered the radiation intensity in the range from 180 to 1850 eV. Plasma temperature was determined by comparison of measured results with radiation spectra obtained by numerical simulation. The values of electron temperature are in good agreement with results of hydro simulations.