Off-axial plasma displacement suitable for antihydrogen production in AEgIS experiment
An application of (1, 0) diocotron mode excitation in low magnetic fields
Istituto Nazionale Fisica Nucleare Sez. Genova,
via Dodecaneso 33, 16146
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: email@example.com
Received in final form: 31 October 2011
Published online: 7 December 2011
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.
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2011