Perveance and ion bunch structure from a 'compact, high-pressure' laser ion source

Journal Article · Wed Dec 15 04:00:00 EST 2010 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3526738· OSTI ID:21532119

Yeates, P ^[1]; Costello, J T; Kennedy, E T ^[1]

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1. National Centre for Plasma Science and Technology (NCPST), Dublin City University (DCU), Dublin (Ireland)

The Dublin City University (DCU) laser ion source (LIS) is a 'compact high-pressure' laser ion source utilizing a table top Q-switched laser. The DCU-LIS combines high laser fluence (F>4 kJ cm{sup -2}), high laser intensity (I>10{sup 11} W cm{sup -2}) with a short field free region (L=48 mm) and high source potential (V{sub ext}>40 kV) in order to offset recombination losses within the plasma and maximize the proportion of highly charged ions which are extracted from the plasma plume. Such a configuration also provides high peak currents (I{sub p}>3 mA), high current densities (J>5 mA cm{sup -2}), and high charge states (Cu{sup 6+}) in the extracted ion-bunch train. However, to obtain and utilize these parameter values in a high pressure LIS requires characterization and control of a number of processes related to ion dynamics and space charge effects on the extracted ions at the plasma plume-anode-extraction gap interface. Relevant issues include electric field distortion, Debye shielding, beam divergence, overfocusing, and perveance (P) in addition to current density profiles for the extracted ion beam. In this paper we focus on these issues and their impact on charge particle extraction and acceleration with a view to elucidating the parameter regimes within which the DCU-LIS performance envelope is optimal.

• OSTI ID: 21532119
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 12 Vol. 17; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ACCELERATION
CURRENT DENSITY
ION SOURCES
LASERS
SPACE CHARGE