摘要:

An intense heavy ion linear accelerator system is being constructed for basic researches on HIF and heavy ion pumped laser at TIT. This accelerator system consists of an RFQ‐Linac, an ECR ion source, a fine‐focusing beam transport system and a fast beam pulsing system. By using this system, ion beams of16O+with currents of 7 mA and an energy of 3.5 MeV will be focused onto a small spot area of about 1 mm2. At present, the maximum beam current obtained from the TIT‐RFQ is 1.6 mA for4He+. The overall status of this linac system and preliminary experiments with beams of4He+are discussed. ©1996 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.50393

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The RFQ‐like funneling concept by Stokes and Minerbo which can be used at low beam energies are studied. It is proposed to modify it to improve the longitudinal stability of the funneling beams. The results of numerical simulations of the funneling concepts are presented. Due to our modification the phase‐width of output beams is reduced from 80° to 35°. The growth of the transverse size is decreased from 6 mm to 2.5 mm, while the content of output beam within radius 0.5 mm is increased from 50% to almost 70%. The electrode shapes of the modified system are presented. ©1996 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.50564

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We report the present status of plasma targets for ion‐plasma interaction experiments which are to run at HIMAC and TIT. The plasma target formed by thez‐pinch of hydrogen gas discharge is constructed for the interaction experiments. Stable pinch process with a relatively long duration of ≊0.5 &mgr;s was observed for initial gas pressure of 0.26 to 0.68 Torr. Prior to the plasma target of a gas flow type, the z‐pinch behavior of a gas‐filled discharge column was studied to compare with a computer simulation using an MHD code. This simulation has led us to understand time dependence of light emission. The behavior of the z‐pinch can be explained in terms of dynamics of shock wave and current sheet. ©1996 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.50394

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Heavy‐ion beams have been considered as a driver for inertial confinement fusion. The interaction of the ion beam with a target plasma is of central importance. A number of studies on the heavy‐ion beam interaction with target plasma are found in the literature 1–4. Reported are the results of a numerical study of an effective charge and nonlinear corrections to the stopping power for heavy ions in plasma. It is important for heavy‐ion stopping that charge states of projectile ions are decided. The effective charge states of beam ions are supposed as Betz formula. It is shown that the stopping power is increased and the stopping range is shortened according to nonlinear effects. The heavy‐ion stopping is simulated at the various temperatures of the target plasma. The target heating of the ion beam and radiation effects are investigated. Energy is decreasing by the varying of the electric and magnetic fields in the target. It is considered to be a collective effect of stopping power. Though it is very small, in fact, there is the energy loss. Here it is shown that by using the PIC code. ©1996 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.50399

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

There is an interest in accelerating atomic nuclei to produce particle beams for medical therapy, atomic and nuclear physics, inertial confinement fusion and particle physics. Laser Ion Sources, in which ions are extracted from plasma created when a high power density laser beam pulse strikes a solid surface in a vacuum, are not in common use. However, some new developments in which heavy ions have been accelerated show that such sources have the potential to provide the beams required for high‐energy accelerator systems. ©1996 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.50361

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Development of an electromagnetic railgun system that utilizes a laser‐induced plasma armature formation has been conducted to investigate the application of the railgun system for high‐speed pellet injection into fusion plasmas. Using the laser‐induced plasma formation technique, the required breakdown voltage was reduced by one‐tenth compared with that for the spark‐discharged plasma. The railgun system successfully accelerated the laser‐induced plasma armature by an electromagnetic force that accelerated the pellet. The highest velocity of the solid hydrogen pellets, obtained so far, was 2.6 km/sec using a 2m‐long railgun. ©1996 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.50546

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Most conventional methods of determining the dipole moment &mgr; are unsatisfactory when applied to transitions between degenerate levels; this is because the overlapping of transitions among magnetic sub‐levels modifies the photo‐excitation behavior in a complex way. To overcome this difficulty, two novel methods of determination are presented. One makes use of differently polarized laser light, and yields a set of excitation curves specific to each polarization. By treating &mgr; as a parameter and fitting the curves through calculations, one can obtain the value of &mgr;. In the other method, a magnetic field is applied to the atom under study in order to raise its degeneracy. As a result, simple Rabi oscillations manifest themselves and one can derive &mgr; directly from their frequencies. These two methods of determining &mgr; are tested on absorption lines in uranium, demonstrating that they work quite well and improve the accuracy of measured dipole moments. ©1996 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.50362

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Spatial and temporal behaviors of laser beam propagating in a atomic vapor have been investigated experimentally. The pulse reshapings of frequency‐chirped laser pulses in the near‐resonant atomic vapor have been demonstrated by making use of atomic samarium vapor. Self‐induced transparency and self‐focusing have also been observed by streak camera. Theses results will be compared with numerical or analytical results in this paper. ©1996 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.50363

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

A rocket powered by a laser‐induced fusion microexplosion is an attractive spacecraft for manned exploration of the solar system because of its potential advantages of high specific impulse and of large specific power. We here discuss some design aspects of a laser fusion rocket. Included are discussion on thrust conversion efficiency, plasma instability in a magnetic nozzle and DT igniter/D3He fuel target design. ©1996 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.50364

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The experiments of a laser‐induced discharge were carried out with a CO2laser radiation in the atmospheric ambient gases under a DC electric field applied. In these experiments, both of the laser‐induced discharge and the plasma production by the CO2laser were suppressed with an increasing DC electric field strength. Although the laser‐produced plasma was generated between the electrodes without DC electric field, both the probability of induced‐discharge and plasma production decreased with the applied voltage across the electrodes. In this paper, the mechanisms of the phenomena for the suppression of the plasma production under applying the electric field between electrodes were discussed. It was found that the attachment processes of electrons most likely played an important role in this phenomena. ©1996 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.50365

出版商:AIP    

年代:1996

数据来源: AIP