Theory of multistage intense ion-beam acceleration

Journal Article · Fri Jun 01 04:00:00 EDT 1990 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.345108· OSTI ID:6874844

Slutz, S A; Desjarlais, M P ^[1]

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1. Sandia National Laboratories, Pulsed Power Theory Division, Albuquerque, New Mexico 87185 (USA)

We present an analytic theory for magnetically insulated, multistage acceleration of high-intensity ion beams, where the diamagnetic effect due to electron flow is important. Our theory is an extension of the single-stage diode theory developed by Desjarlais (Phys. Rev. Lett. {bold 59}, 2295 (1987)), based on a self-consistent calculation of the virtual cathode position, which has been successful in modeling Applied-{ital B} ion diode experiments on several accelerators. The new theory incorporates a finite injection energy {ital qW} for the beam ions. We have found a critical voltage {ital V}{sub 1}({ital W}) that corresponds to {ital V}{sub *} of the single-stage theory. As the voltage approaches {ital V}{sub 1}, unlimited beam-current density can penetrate the gap without the formation of a virtual anode because the dynamic gap goes to zero. At voltages lower than {ital V}{sub 1}, a sufficiently large injection current will cause the formation of a virtual anode in response to the large beam space charge. Furthermore, we have found that unlimited beam current can penetrate an accelerating gap operated above a second critical voltage {ital V}{sub 2}({ital W}). At voltages below {ital V}{sub 2}, there is a maximum steady-state current that can be transmitted through the gap. The critical voltage {ital V}{sub 2} is smaller than {ital V}{sub 1} and is unique to the multistage theory. If fluctuations allow electron transport across magnetic field lines so that any virtual anode is neutralized, {ital V}{sub 2} goes to zero for all beam injection energies. This effect can be used to test the importance of field fluctuations on the electron dynamics in magnetically insulated ion acceleration gaps.

• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6874844
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 67:11; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430200* -- Particle Accelerators-- Beam Dynamics
Field Calculations
& Ion Optics
ACCELERATION
ANALYTICAL SOLUTION
BEAM CURRENTS
BEAMS
CONFINEMENT
CURRENTS
DIAMAGNETISM
DIODE TUBES
ELECTRON TUBES
FLUCTUATIONS
INERTIAL CONFINEMENT
ION BEAM FUSION REACTORS
ION BEAMS
MAGNETIC FIELDS
MAGNETISM
PLASMA CONFINEMENT
SELF-CONSISTENT FIELD
THERMONUCLEAR REACTORS
VARIATIONS