title: Compression of positron clouds in the independent particle regime.
abstract: The application of an asymmetric dipolar electric field rotating at a frequency close to that of the axial bounce of a collection of trapped positrons has, in the presence of a low pressure molecular gas to provide cooling, been used to achieve compression of the cloud. A theory of this effect has been developed for a Penning trap potential, with the cooling modeled in the Stokes viscous drag approximation. Good agreement between the theory and measurements of the frequency dependence of the cloud compression rate has been found, establishing that the phenomenon is a new form of sideband cooling.
authors.affiliation: Department of Physics, College of Science, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom.
authors.forename: C A
authors.initials: CA
authors.lastname: Isaac
authors.forename: C J
authors.initials: CJ
authors.lastname: Baker
authors.forename: T
authors.initials: T
authors.lastname: Mortensen
authors.forename: D P
authors.initials: DP
authors.lastname: van der Werf
authors.forename: M
authors.initials: M
authors.lastname: Charlton