Nonlinear and Inertial Magnetic Structures in Emhd Plasmas

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

This award is made in response to a proposal submitted to and reviewed under the NSF/DOE Partnership in Basic Plasma Science and Engineering joint solicitation NSF 09-596. The award provides funds to support the broader impact activity of dissemination of research results by participation in annual conferences. The overall research effort, which does not support this broader impact activity, is being funded separately by the DOE under contract to UCLA (Grant DE-FG02-10ER55081). Research on magnetic holes and bubbles in dense plasmas will be performed. These are depletions and enhancements of magnetic fields in plasmas produced by nonlinear effects. Such structures exist in many plasmas from astrophysical to nanometer scales. In the laboratory the physics of these phenomena will be studied under controlled conditions. Bubbles and holes will be investigated in a parameter regime called electron magnetohydrodynamics, where only the electrons interact with the magnetic field, but not the ions, while both species are coupled via space charge electric fields. This leads to many unexplored electromagnetic effects which are of interest in magnetic reconnection, turbulence, particle acceleration and heating. Specifically, the proposed experiments will induce localized magnetic fields with loop antennas driven by pulsed or oscillatory currents. Magnetic holes are generated when the induced plasma field cancels an ambient field. Magnetic bubbles in unmagnetized plasmas are produced when the induced plasma field is strong enough to magnetize the electrons and allow whistler modes to exist inside the bubble. The study of magnetic holes and bubbles is new and fundamental and has potential impact on many areas in plasma physics. The proposed research benefits society through discoveries which also lead to practical applications. For example, ongoing research into helicity properties of whistler vortices led to the development of a novel directional antenna which could be used in space to transmit or receive signals in a preferred direction. Comparable research is only performed in Russia.