Eur. Phys. J. D 65, 499-504 (2011)
https://doi.org/10.1140/epjd/e2011-20552-x

Regular Article

Off-axial plasma displacement suitable for antihydrogen production in AEgIS experiment

An application of (1, 0) diocotron mode excitation in low magnetic fields

¹ Istituto Nazionale Fisica Nucleare Sez. Genova, via Dodecaneso 33, 16146 Genova, Italy
² Università di Genova, via Dodecaneso 33, 16146 Genova, Italy
³ Università di Trento and INFN, Gruppo Collegato di Trento, via Sommarive 14, Povo, 38050 Trento, Italy
⁴ Physics Institute, Zurich University, 8057 Zurich, Switzerland

^a e-mail: testera@ge.infn.it

Received: 26 September 2011
Received in final form: 31 October 2011
Published online: 7 December 2011

Abstract

Antihydrogen experiments are currently based on non neutral electron, positron or antiproton plasma manipulation techniques in cylindrical Malmberg-Penning traps. An experimental study of a plasma manipulation technique based on off-axis diocotron displacement is presented. The use of the autoresonant excitation of (1, 0) diocotron mode of pure electron plasma allows a precise positioning of the plasma by moving it across the magnetic field and allows dumping such plasma in a desired angular position. The experimental procedure described here will pave the way to positron loading into an off-axial Penning trap terminated with a positronium converter target as it is proposed for the AEgIS experimental apparatus. The technique was studied over a range of confining magnetic field values and reproduces experimental conditions similar to most of the currently running antihydrogen experiments.

The efficiency of the autoresonant excitation – in terms of plasma expansion rate and particle loss – is analyzed, studying the behaviour of electron plasma subjected to large off-axial displacements, showing that this method fulfills the requirements imposed by the AEgIS experiment.