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\"Recent results from gas dynamic trap experiment\".
| Author: | Ivanov A.A. |
| Coauthor: | A.V.Anikeev, P.A.Bagryansky, P.P.Deichuli, V.V.Maximov, S.V.Murakhtin, A.A.Lizunov, Yu.A.Tsidulko |
| Institution : | Budker Insitute of Nuclear Physics |
| Abstract text: | Axially symmetric magnetic mirror device Gas Dynamic Trap (GDT) is considered as an attractive option for development on its basis a 14 MeV neutron source for fusion materials testing. In the recent experiments on-axis transverse beta exceeding 0.4 in the fast ion turning points near the end mirrors has been achieved. The plasma has been heated by 4 MW injection of 15-17 keV deuterium neutral beams at the center of the device, which at the same time produced anisotropic fast ions. Neither enhanced transverse losses of the plasma nor anomalies in the fast ion scattering and slowing down were observed. This observation confirms the theoretically predicted magnetohydrodynamic stability of the plasma in the axially symmetric confinement devices with average min-B, like GDT. The measured beta value is close to that expected in different versions of the GDT based 14 MeV neutron source. Formation of axially peaked profile of fast ion density, which results in strong peaking of the neutron flux, is a key issue for the GDT-based neutron source. Recent experiments demonstrated that neutron yield is peaked near the turning points of anisotropic deuterons, as expected. This observation is in agreement with previous measurements of the angular distribution of the fast ions and results of numerical simulations of fast ion relaxation. It was observed that the neutron emission is localized in a region with radial extent of about Larmor radii of the fast ions. Possible mechanism of formation of the narrow radial profile is discussed in the paper. |
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