An electron–positron beam–plasma instability

Abstract

Using a new technique to generate cold electron beams, an electron-beam positron-plasma experiment was performed in a previously unexplored range of energies. An electron beam, formed from a thermalized room-temperature electron plasma, is transmitted through a positron plasma stored in a quadrupole Penning trap geometry. The transit-time instability, which is excited by the beam, was previously studied using a hot-cathode electron gun. The large beam energies produced by the cathode did not permit an investigation of the instability in the interesting range of energies near its onset. Using a new 0.1 eV energy width electron beam, we have reinvestigated the system. The experimental data are compared with the results of a theoretical model, also described in this paper. The theory employs a linearized cold fluid and Vlasov approach to model the plasma and beam dynamics, respectively. The data and predictions are in good agreement over the broad range of energies and beam currents studied.

Positron Plasmas in the Laboratory

“…Good, quantitative agreement between theory and experiment was achieved. The theoretical and experimental results were published last year in a paper in Physics of Plasmas [17]. While a multitude of theoretical papers have studied electron-positron plasmas (largely in the context of astrophysical plasmas), our work represents the first experiment on the electron-positron plasma system.…”

“…While a multitude of theoretical papers have studied electron-positron plasmas (largely in the context of astrophysical plasmas), our work represents the first experiment on the electron-positron plasma system. [4,6,17,24] The cold positron beam also enabled many new positron atomic-physics experiments. A number of important results were obtained during the grant period.…”

Electrostatic solitons in unmagnetized hot electron–positron–ion plasmas

“…A lot of efforts have been made to create e-p plasmas in the laboratory experiments [12]. The lower energy electron beams are injected into the positron plasma to study instabilities and collective effects in e-p plasmas.…”

Paul trap for pure positron plasma – A prelude to electron–positron plasma in a laboratory

“…EPP have nevertheless, not been created so far in the laboratory such that both species are confined simultaneously over a common volume. Surko [1,2] has, however carried out electron-positron beam plasma experiment where a low energy electron beam is passed through positron plasma in a cylindrical/quadrupole trap. The studies of unique linear modes in plasmas, with equal mass and oppositely charged species can be extended further to magnetized EPP.…”