Propagation of intense plasma and ion beams across B-field in vacuum and magnetized plasma

Abstract

This paper summarizes experimental results on the injection and transport of intense, wide cross-section H ϩ plasmã PB!, and ion beams~IB!, in vacuum and ambient H ϩ plasma across an applied B-field. The injection of plasma and ion beams into magnetic confinement devices have the potential to heat and support current in these systems~e.g., field-reversed configurations!. The translational energies of the PB and IB ranged between E pb ϭ 60 to 120 eV and E IB ϭ 60 to 120 keV, with temperatures and densities in the range of T b ; 2 to 10 eV, n b ; 10 12 to 10 13 cm Ϫ3 , and T b ; 200 eV, n b 10 10 to 10 11 cm Ϫ3 , respectively. Compared to earlier studies~Peter, 1979;Wessel et al., 1988 Wessel et al., , 1990!, this research extends the experimental parameter space to higher beam current densities~up to 30 A0cm 2 ! and higher B-field strengths up to 1.6 kG. The PB and IB were both about 10 cm in diameter at the injection port, and the ratio of beam specific energy to ambient B-field specific energy, b, was in the range of 0.1 to 10. Ratios of beam Larmor radius to beam size, r, ranged from 10 Ϫ1 to 1 and 1 to 10 for the PB and IB, respectively. Cross B-field propagation of the PB in vacuum was undeflected as a whole with a sharp increase~one order or more! in the current density of the central beam core at B-field levels . 1 kG accompanied by a significant loss of beam peripheral layers, beam "braking" and preferential beam expansion along the B-field lines. Cross B-field propagation of the PB in ambient plasma did not differ substantially from the case without B-field, that is, no deflection of the PB as a whole, which could be due to an insufficient neutralization of the induced E-field inside the PB. Cross B-field propagation of the IB in ambient plasma followed a single particle trajectory deflection with a simultaneous significant loss of IB intensity without any detectable bunching, indicating an adequate shorting of the polarization E-field inside the IB.

Plasma and ion beam injection into an FRC

“…In our earlier studies of beam injection across a uniform B-field in vacuum [4] both beams propagated un-deflected with significant losses of their peripheral layers. In the case of plasma beam injection the current density in the surviving central core showed a dramatic increase.…”

“…2B. See [4] for a more detailed discussion on cross B field injection of plasma and ion beams in vacuum and ambient plasma. …”

Slow neutron reactions in inverse kinematics for isotope production: a primer

“…In ion-beam sources, the beam extraction is through the Coulomb forces whereas in real plasma beam sources, the Lorenz-forces accelerate and extract the entire plasma [10]. Ion current densities of a few Amperes/cm 2 and peak densities of a few hundred Amperes/cm 2 have been achieved in IB and PB systems, respectively [11]. Higher average output power and higher repetition rates in pulsed PB systems are becoming available.…”

Surface wave excitation by a density modulated electron beam in a magnetized dusty plasma cylinder

“…It can be excited by an electron beam (Liu & Tripathi, 2000;Prakash & Sharma, 2009;Girka et al, 2011a;2011b), by an ion beam (Girka et al, 2011a;2011b), by attenuated total reflection (ATR) configuration (Kretschmann & Raether, 1968;Kretschmann, 1971;Fink & Schneider, 1975), by ripples of suitable wave number over the metallic interface (Liu & Tripathi, 2000), by light via prism coupling (Chen et al, 2011), or by laser (Anisimov et al, 1988;Parashar et al, 1998;Bouhelier et al, 2007). The interaction of laser beam with plasma eigenmodes is also an important area of research (Ghorbanalilu, 2012;Verma & Sharma, 2011;Sharma et al, 2010;Saini & Gill, 2006;Anderson et al, 2005;Paknezhad & Dorranian, 2011) in recent years.…”