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Experimental investigation of the interaction of multiple magnetized current carrying plasma channels
| Author: | Furno I. |
| Coauthor: | T. Intrator, E. Hemsing |
| Institution : | Los Alamos National Laboratory |
| Abstract text: | The interaction and stability of magnetized flux ropes in magnetically confined plasmas are of at most importance to understand MagnetoHydroDynamic (MHD) equilibrium properties of these systems. Three-dimensional (3D) effects are expected to play an important role in a variety of innovative, confinement schemes such as FRC, Stellarators and Spheromaks. At Los Alamos National Laboratory, the Reconnection Scaling Experiment (RSX) is a unique facility that can create one, two, three or more current carrying flux ropes in an MHD experiment. Magnetic reconnection is induced between parallel current channels in a truly 3-D geometry and we study the dynamical evolution. In RSX, plasma guns are used to inject magnetic helicity into hydrogen or argon plasma column (r = 2 cm radius, L = 0.2-3 m length). Multiple, axial current carrying flux tubes up to 1 kA are created in a 4 m linear vacuum vessel, immersed in an axial magnetic field. The azimuthal (B? = 0-100 Gauss) and axial (Bz = 0-1000 Gauss) magnetic field components as well as the plasma density (1012-1014 cm-3) can be varied independently. In the present work, the interaction and MHD stability of two flux ropes are studied using time and space resolved magnetic field and electrostatic probe measurements. To date, preliminary experiments in the collisional regime and in the presence of a strong guide magnetic field (Bz/Brec>20) show the formation of current sheet in between the two current channels. Propagation of a rarefaction density wave in the current sheet is measured and seems to be related to intrinsic 3-D properties of the reconnection region. In future experiments, more collisionless regimes will be explored, and the influence of the guide magnetic field on the dynamics of the current sheet and the reconnection rate will be investigated, as well as the non-linear evolution and kinking of flux ropes |
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