NICOP - Study of the implosion of a magnetized gas-puff column with pre-embedded axial fields
Abstract
Study of the implosion of a magnetized gas-puff column with pre-embedded axial fields:Background and RelevanceThe Plasma Physics Division of NRL focuses on the study of plasma phenomena that occur in numerous S&T applications including the dynamics of Earth s ionosphere and magnetosphere, new high-power laser systems, laser propagation in atmosphere, laser-matter interactions in HEL applications, detection of laser beams in air for counter-HEL applications, high-efficiency and durable white light sources, and new high-power, compact accelerators for various defense programs. The comprehensive knowledge and models that NRL has developed in plasma science provide guidance to US plasma scientists in defense and other fields. NRL also develops high-fidelity simulations of various plasma phenomena and provides essential formulas to the plasma community at large. One of the highly-nonlinear phenomena that are under investigation is the coupling between plasma motion and magnetic field evolution. Recently, plasma research has focused on the study of compressed magnetized plasmas but the evolution of magnetic fields is not well understood in particular when flux compression occurs. Various magnetic field measurement techniques developed so far have limitations especially for observing the fast transient behavior of magnetic field evolution in plasmas. Some of the current methods are intrusive and affect the measurements, some provide only averaged measurements along the line-of-sight, and some produce a combined estimate of plasma density and magnetic field that have to be numerically separated by deconvolution. Furthermore, none of the current techniques is suited for pulsed-power applications. InnovationThe proposed study will apply advanced, non-intrusive, spectroscopic techniques to provide unprecedented measurements of the plasma parameters and the magnetic field evolution. The configuration will use a cylindrical gas puff, with a pre-embedded, initially uniform, axial magnetic field. An axial current from a pulsed-power generator will be applied to ionize the gas and accelerate the plasma inward, compressing the axial field. The spectroscopic measurements will determine the time-resolved plasma electron density, electron temperature, charge state distribution, and ion velocity distributions. Thes results of these methods will be combined with laser-ablation doping techniques to obtain the 3D spatially-resolved parameters of the magnetic field and plasma. Axial and azimuthal magnetic fields will be measured simultaneously to increase the reliability of the results by eliminating the effects of shot-to-shot variability. The proposed approach will enable scientists to investigate accurately the evolution of the magnetic field and the effect of the initial conditions on the nature of the compression. Various parameters and phenomena will be investigated, including the effects of the axial magnetic field on the current distribution, the pressure balance at stagnation, the role of the electrodes on the axial field distribution, the partitioning between the electromagnetic energy and plasma energy, as well as the energy transfer among the various plasma constituents. ONR HQ ConnectionRyan Hoffman, Code 35, strongly supports this proposal and will co-fund it. ONR Code 35 is especially aware that many plasma scientists at NRL will collaborate and benefit from this research and from the guidance that Prof. Maron provides to NRL. Desired OutcomeAccurate measurement of proposed plasma and magnetic field parameters, and estimation of the derived properties. Publications in peer reviewed journals. Strong collaboration with the Plasma Physics Division of NRL. I recommend funding this proposal.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 23, 2016
- Source ID
- N629091612192
Entities
People
- Yitzhak Maron
Organizations
- Office of Naval Research
- United States Navy
- Weizmann Institute of Science