Intense negative hydrogen ion production in high-power diodes

Papadichev, V.A.

doi:10.1017/s0263034600002408

Cited by 6 publications

References 9 publications

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Production and acceleration of pulsed kiloampere currents of H− and subkiloampere currents of C−, F−, I−, and Pb− ions

Mozgovoy

Papadichev

1994

Review of Scientific Instruments

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Experiments on acceleration of various negative ions in a high-power coaxial diode with magnetic insulation are described. Various methods of initiating cathode plasma for H− production were tried: surface discharge of a dielectric by the prepulse in two cathode configurations and laser illumination of a dielectric cathode. A new more universal method of cathode plasma initiation was developed, allowing us to produce various species of negative ions including metallic ones. Rather rare plasma was injected from a plasma gun at the outer surface of the anode. This plasma penetrates partially into the diode through holes, and positive ions are extracted and accelerated by the negative prepulse or/and main voltage pulse of the diode and bombard the cathode surface. The energy deposition and cathode plasma parameters can be easily varied by orders of magnitude by changing near anode plasma density (by varying charging voltage of plasma gun and time delay between plasma gun pulse and prepulse and main voltage pulse of the diode) and ion acceleration voltage. Up to 30 A/cm2 of H− ion current density was recorded, as well as about 1 A/cm2 for C−, 0.3 A/cm2 for F−, and 0.1 A/cm2 for I− and Pb−.

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Production and acceleration of pulsed kiloampere currents of H− and subkiloampere currents of C−, F−, I−, and Pb− ions

Mozgovoy

Papadichev

1994

Review of Scientific Instruments

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Various ways of cathode plasma formation to produce up to 200 A/cm2 of H− and 0.1–1 A/cm2 of C−, F−, I−, and Pb− ions

Mozgovoy

Papadichev

1994

Review of Scientific Instruments

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Various ways of initiating cathode plasma for producing high-current densities of negative ions were tried at the P. N. Lebedev Physical Institute. The first was prepulse induced electrical breakdown on the surface of a dielectric inserted between two metallic parts of a cathode. A second method was surface discharge of a perforated dielectric sleeve on a metallic cathode rod, which yielded acceptable plasma parameters for larger prepulse voltages than in the first case. A circuit was developed and tested to supply an externally applied prepulse with changeable parameters. The third method employed laser illumination of a cathode dielectric surface to initiate cathode plasma. No prepulse was used in this case and nearly the same current densities of negative hydrogen ions were obtained as with the first method of plasma initiation. A new more widely applicable way of cathode plasma initiation was proposed recently and studied experimentally. This method allows one to produce negative ions of various chemical elements in high-current pulsed diodes. It utilizes cathode bombardment by positive ions extracted from near-anode plasma injected at the outer surface of the anode and which penetrates partially through anode holes into the diode. Plasma parameters can be easily varied by changing plasma gun voltage and time delay between plasma gun pulse and diode voltage pulse. Current densities of up to 30 A/cm2 of H− and about 1 A/cm2 of C−, 0.3 A/cm2 of F− and 0.1 A/cm2 of I− and Pb− were recorded using this last method of cathode plasma production. The merits and disadvantages of all methods of cathode plasma production are discussed.

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Generation of Nonlinear Force Driven Blocks from Skin Layer Interaction of Petawatt-Picosecond Laser Pulses for ICF

Hora

Chen

et al. 2004

Plasma Sci. Tech.

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The discovery of the essential difference of maximum ion energy for T W -p s laser plasma interaction compared with the 100 ns laser pulses[lI led to the theory of a skin layer model [ ' I where the control of prepulses suppressed the usual relativistic self-focusing. The subsequent generation of two nonlinear force driven blocks has been demonstrated experimentally and in extensive numerical studies where one block moves against the laser light and the other block into the irradiated target. These blocks of nearly solid state density DT plasma correspond to ion beam current densities L31 exceeding lo1' A/cm' where the ion velocity can be chosen up to highly relativistic values. Using the results of the expected ignition of DT fuel by light ion beams, a selfsustained fusion reaction front may be generated even into uncompressed solid DT fuel similar to the Nuckolls-Wood [41 scheme where 10 kJ laser pulses produce 100 MJ fusion energy. This new and simplified scheme of laser-ICF needs and optimisation of the involved parameters.

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Intense negative hydrogen ion production in high-power diodes

Cited by 6 publications

References 9 publications

Production and acceleration of pulsed kiloampere currents of H− and subkiloampere currents of C−, F−, I−, and Pb− ions

Production and acceleration of pulsed kiloampere currents of H− and subkiloampere currents of C−, F−, I−, and Pb− ions

Various ways of cathode plasma formation to produce up to 200 A/cm2 of H− and 0.1–1 A/cm2 of C−, F−, I−, and Pb− ions

Generation of Nonlinear Force Driven Blocks from Skin Layer Interaction of Petawatt-Picosecond Laser Pulses for ICF

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