摘要:

Experiments to generate large magnetic fields by flux compression have been performed in a z‐pinch. Two z‐pinch plasma configurations were investigated: (i) a novel plasma liner developed from a thin cylindrical soap film and (ii) a conventional gas pinch formed in a uniform cylinder of gas. The apparatus, experiments and the results obtained are described in this paper. A comprehensive investigation of the gas pinch shows that an optimum set of conditions exists, for given discharge parameters, for obtaining the highest magnetic field. Using a current of 500 kA with&tgr;1/4 = 2 &mgr;s, an initial magnetic field of 0.3 T has been compressed to 38 T, a compression ratio of over 120. The scaling of the attainable peak magnetic field with discharge parameters has been studied and compared with simplified models of the compression.

ISSN:0094-243X    

DOI:10.1063/1.2949219

出版商:AIP    

年代:1994

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.2949220

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

An HD implosion of a pellet in spherical geometry cannot ignite advanced fuels. In cylindrical geometry, where the region of the spark is accessible to other means of energy delivery, a detonation can be started and propagated even in pure deuterium. A mechanism which could achieve this, based on the compression of a fibre by a Z‐pinch driven by a liner implosion is described.

ISSN:0094-243X    

DOI:10.1063/1.2949221

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

There is considerable demand in the scientific community for a neutron generator with an output of 106–108neutrons/second (n/s) that can be switched on or off, emit fusion neutrons, be self‐calibrating, and offer portable operation. An Inertial Electrostatic Confinement (IEC)‐based neutron generator is proposed to meet these needs.In an IEC device, ion beams are injected into a spherical vacuum vessel containing one or more sets of spherical wire grids. A high fusion rate is generated in a dense plasma region created in the center of the innermost grid by intersecting ion beams and the associated potential well structure. Here, we describe a unique configuration, termed the IECGD, where a gaseous discharge in a single‐gridded device serves as the ion source. Operation in the newly discovered “Star” discharge mode maximizes the effective grid transmission factor for ions. This configuration, then, provides a simple, rugged, low‐cost fusion neutron source, operating in the 106D‐D n/s or 108D‐T n/s range. The extension to an intense MeV proton source is also possible.Experimental results for the IECGD are presented, with a discussion of corresponding theoretical studies using a Vlasov‐Poisson solver (IXL) and an electrostatic particle‐in‐cell code (PDS1).

ISSN:0094-243X    

DOI:10.1063/1.2949222

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

A powerful capacitor bank was designed and built to investigate the possibility of increasing the neutron yield up to the 1013–1014DD neutrons per pulse and to generate ultrahigh magnetic fields up to 1GG. The bank consists of 60 independent 20 kJ modules. The module contains four 5 kJ, 40 kV capacitors and a gaseous spark gap. Each module is connected to the load by means of four low inductive coaxial cables, each about 11 m long. The inductance of module and output cables is 100 nH. The spark gaps are fired by a generator wich consists of a capacitor, a water pulse‐forming line and an untriggered gaseous spark gap. The bank has a stored energy of 1.2MJ, capacitance of 1.5 mF, inductance of 3 nH, operates at voltages up to 40kV, and providesI ∼ 13 MA, 5 mks risetime current pulse to a 4 nH load.

ISSN:0094-243X    

DOI:10.1063/1.2949223

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

The implosion of a dense &thgr; pinch plasma driven by an annular Z‐pinch is considered. A cryogenic fiber is coaxially located within an annular gas jet Z‐pinch. The imploding Z‐pinch traps an applied axial magnetic field and conserves flux. The axial magnetic field increases due to compression of the outer pinch and attains values in excess of tens of megagauss with field risetimes of order,dB/dt = 10MG/ns, with an order of magnitude shorter rise time than the Z‐pinch current. An azimuthal &thgr;‐current is induced on the fiber surface with a similar rise time; which could not otherwise be achieved in a simple fiber Z‐pinch due to the large inductance initially presented by the small diameter axial plasma. The implosion transfers Z‐pinch kinetic energy to the magnetic field and then to the &thgr;‐pinch. The final plasma pressure of the &thgr;‐ pinch exceeds the magnetic pressure so that the &thgr;‐pinch then expands‐the only confinement is inertial. To reach break‐even and beyond, with reasonable Z‐pinch currents, we increase the radiative losses by seeding the discharge with high Z impurities. Seeding a cryogenic Hydrogen‐like fiber with high Z‐impurities would substantially reduce the preheat in the &thgr;‐pinch, over a non‐seeded discharge, and increase the final density by radiative collapse. Thusn&tgr; ∼ 1014 cm−3‐s could be reached with a confinement time of 0.01 ns and density of 1025cm−3predicted in this paper.

ISSN:0094-243X    

DOI:10.1063/1.2949224

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Assuming that a quasi‐static z‐pinch formed from a frozen DT fiber is stable as long as the current is rising, and that the magnetic energy of the pinch can be recovered with > 90&percent; efficiency, it is shown that a pulsed energy‐producing cycle is possible yielding about 7.5MJ per pulse from a 30 cm long fiber. Practical details are given of a reactor that would operate at a pulse repetition frequency of 40 Hz, and have an output of about 100 MW(e).

ISSN:0094-243X    

DOI:10.1063/1.2949226

出版商:AIP    

年代:1994

数据来源: AIP