Institutskolloquium des IPP 2016

Vortragender: Dr. Eve Stenson

En route to electron/positron pair plasmas

Institutskolloquium
The large mass imbalance between ions andelectrons — and the resulting separation of the two species’ length and timescales — is a cornerstone of traditional plasma physics.  Therefore, to consider the novel behavior ofa “pair plasma”, comprising particles with opposite charge but equal mass, isto revisit much of plasma physics from the ground up.  To date, over a thousand journal articleshave been devoted to this topic, describing a variety of analytical andcomputational treatments, but the experimental side of the investigation isstill in its nascence.  Laboratorycreation and confinement of electron/positron plasmas would enable the firsttests of many theory and simulation predictions (e.g., the stabilization ofanomalous transport mechanisms), with implications for our understanding notonly of pair plasmas (and astrophysical phenomena in which they play a role)but also of traditional electron/ion plasmas. This is the goal of the APEX/PAX (APositron-Electron eXperiment/PositronAccumulation eXperiment) project, in which a world-class positron beam(NEPOMUC, at FRM-II) is being combined with state-of-the-art techniques fromnon-neutral plasma physics.  This talkwill give an overview of milestones achieved in the past several years,including the demonstration of efficient ExB injection and subsequentconfinement (τ = 3-5 ms) of cold positrons in a dipole magnetic field, as wellas the upcoming upgrade from a supported permanent magnet to a supported HTSC(high-temperature superconductor) coil, then to a levitated HTSC coil suitablefor the simultaneous confinement of electrons and positrons. [mehr]
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