Simple model of beam transport in low-pressure ion-focused regimes

Nonlinear Theory Modeling Electron Beam Constriction in a Pulsed Power Discharge

“…T HE propagation of charged beams transported through neutral gas or plasma has been studied in detail in [1]- [33]. Often, the charged beam will propagate through the gas or plasma in a pinched mode [1], [22], [29], instead of breaking up as one would expect from like-charge coulombdriven particles.…”

“…Often, the charged beam will propagate through the gas or plasma in a pinched mode [1], [22], [29], instead of breaking up as one would expect from like-charge coulombdriven particles. Typically, an electron beam enters a gas (or plasma), it ionizes this gas and ejects the light electrons generated from the ionization process.…”

“…This neutralizes the beam's space charge. Then, the electron beam can constrict due its own magnetic forces; no external magnets are needed [1]- [5], [7], [22], [24], [29].…”

“…The transient nature of this problem is difficult and is usually simplified using a number of plausible assumptions such as that the instantaneous expulsion of plasma electrons, the attainment of partial or total equilibrium by way of a force balance condition, or the neglect of nonlinear terms for simplicity [1]- [3], [7], [22], [25]. The dynamics of the expulsion of plasma electrons are usually examined using particle codes.…”