摘要:

Two economical designs for high voltage amplifiers are described, and the performance of constructed units is characterized. The first amplifier is based on a design originating from the non‐neutral plasma group at UC San Diego, and is useful for driving capacitive loads such as the containment rings of Penning traps. The second is based on a design published by the Jones group of the University of Utah Chemistry Department, and is designed to power radio‐frequency (rf) guides and traps. Complete design specifications including schematics, PC board files and circuit simulation inputs are available for those interested in building either amplifier. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635181

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The confinement of ions in a purely electrostatic, three‐electrode configuration is predicted. The electric potential within the trap is calculated by numerically solving Laplace’s equation using a sequential over‐relaxation method. The classical trajectory of a proton is computed by numerically solving the equations of motion. Parameters that result in particle confinement are provided. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635182

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The ATHENA and ATRAP collaborations have recently created large numbers of untrapped anti‐hydrogen atoms. The most commonly suggested scheme for trapping the anti‐hydrogen is to use a Minimum‐B trap. Unfortunately, the Minimum‐B fields are very likely to destroy the confinement of the anti‐hydrogen constituents; the positrons and anti‐protons, which are themselves held in double‐well Penning‐Malmberg traps. The reasons for the loss of confinement, and modifications to the Minimum‐B trap that may alleviate this problem, are discussed in this paper. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635183

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Inertial Electrostatic Confinement of fusion ions in a modified Penning trap is further modified to include a mechanism for low‐power recirculation of electrons via a diverter electrode placed in the low‐field, cusp region of the trap. The locally divergent magnetic field lines act as a magnetic nozzle to extract energy bound up in the angular momentum of the larmor gyrations of the electrons, enabling the diverter potential to be close to that of the emitter while still collecting scattered electrons. In theory, the diverter recirculates a large fraction of the scattered core electron population back to the emitter through a much smaller potential difference, thereby reducing the overall power consumption for a given collisional diffusivity in the core region and improving overall system efficiency. Modeling of the general system is presented which suggests a power density that is too low to be practical for power generation unless ion density enhancement via a POPS type mechanism is realized. However, this technology is suggested as a potential candidate for an experimental plasma target, neutron source. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635184

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Various interdisciplinary issues are identified that are associated with the prospect of producing an electron‐free fusion plasma. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635185

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

A rigorous extension of the contour dynamics technique to systems with a cylindrical boundary is presented. The new technique makes use of the image‐charge method in order to obtain an analytic expression for the velocity field in terms of line integrals on the contours. Selected results are presented to show the high accuracy attainable with the method. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635186

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The three‐dimensional evolution of a pure electron plasma in a Penning‐Malmberg trap is studied by means of a newly developed particle‐in‐cell code in the frame of a cold fluid guiding center electrostatic approximation. Results obtained both in the trapped plasma case and in the beam propagation regime are shown. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635187

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

All experiments, which have been proposed so far to model the magnetorotational instability (MRI) in the laboratory, involve a Couette flow of liquid metals in a rotating annulus. All liquid metals have small magnetic Prandtl numbers, Pm ∼ 10−6, the ratio of kinematic viscosity to magnetic diffusivity. With plasmas both large and small Pm are achievable by varying the temperature and the density of plasma. Compressibility and fast rotation of the plasma result in radial stratification of the equilibrium plasma density. Evolution of perturbations in radially stratified viscous and resistive plasma permeated by an axial uniform magnetic field is considered. The differential rotation of the plasma is induced by theE×Bdrift in applied radial electric field. Global unstable eigenmodes are calculated by our newly developed matrix code. The plasma is shown to be MRI unstable for parameters easily achievable in experimental setup. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635188

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

For the first time, an experimental study on helical nonneutral plasmas is performed on the Compact Helical System (CHS) device. (1) Remarkably, despite being launched from the outside of closed magnetic surface, the injected electrons travel across the magnetic field and penetrate deeply inside the magnetic surfaces. This penetration of electrons is caused by a collisionless mechanism that has never been observed in past toroidal nonneutral plasmas confined in axisymmetric geometry. (2) The penetrated electrons form a helical non‐neutral plasma inside the magnetic surface. The electron density is about 1011–13m−3much smaller than the Brillouin density limit. (3) The stable phase of the helical non‐neutral plasma continues only for 1 – 4 ms and then starts to disrupt. About 50 kHz of disruptive instability is observed. This frequency and the other parameters related to the onset time of the instability suggest an ion‐related instability as the possible mechanism. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635189

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The physics of non‐neutral plasmas confined on magnetic surfaces is discussed. The Columbia Non‐neutral Torus (CNT), a table‐top ultrahigh vacuum stellarator being constructed at Columbia University, is being built to systematically study non‐neutral plasmas confined on magnetic surfaces. The experimental design is discussed in the context of relevant physics parameters, such as the number of Debye lengths in the device, and the parallel versus perpendicular time scales. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635190

出版商:AIP    

年代:1903

数据来源: AIP