Radial constant of motion for particles in magnetic mirror fields
2014 (English)In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 56, no 9, 095026- p.Article in journal (Refereed) Published
It is crucial for magnetic fusion devices that particle confinement occurs for long periods in a magnetic flux tube, and radial loss from the flux tube by a collision-free radial drift needs to be eliminated. Longitudinal, as well as radial, confinement is required. Two standard constants of motion, the energy and the magnetic moment of the gyrating particle, provide longitudinal confinement. A third constant of motion, which implies bounded radial motion, would be sufficient for radial confinement, but it is often impossible to identify such an invariant. A closed form expression for a radial invariant is derived for magnetic mirrors with a stabilizing quadrupolar field. A weak radial electric field, controlled by electrically biased endplates, is a tool for making a collision-free motion radially bounded in open systems. Experimental results in such magnetic confinement schemes indicate a qualitative agreement with our predictions for the existence of a radial invariant. Voltage and power requirements for the biased endplates are vanishingly small if the magnetic drifts are minimized in the magnetic field design. The power requirements to sustain the biased potentials are expected to be vanishingly small for a gross stable plasma.
Place, publisher, year, edition, pages
2014. Vol. 56, no 9, 095026- p.
radial invariant, radial constant of motion, radial drift loss, magnetic mirror, mirror machine, hybrid reactor, biased endplates
Physical Sciences Engineering and Technology
Research subject Engineering Science with specialization in Science of Electricity
IdentifiersURN: urn:nbn:se:uu:diva-234178DOI: 10.1088/0741-3335/56/9/095026ISI: 000341854100036OAI: oai:DiVA.org:uu-234178DiVA: diva2:755687