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TJ-II:NBI1 vs. NBI2 heated plasma comparison: Difference between revisions
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TJ-II:NBI1 vs. NBI2 heated plasma comparison (view source)
Revision as of 15:33, 19 January 2022
, 19 January 2022→Description of the activity
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== Description of the activity == | == Description of the activity == | ||
At TJ-II, NBI heated plasmas show differences that depend on the injection direction, co- or counter-injection (NBI1 or NBI2, respectively). Whereas the evolution of the electron temperature and density profiles are alike in the two heating schemes, the radial electric field and density turbulence profiles evolve differently, ending up in a higher density limit and higher energy content in plasmas heated with counter-NBI (NBI2). Besides, some differences in the plasma radiation profiles are detected whose evolution is presently being studied. | At TJ-II, NBI heated plasmas show differences that depend on the injection direction, co- or counter-injection (NBI1 or NBI2, respectively). Whereas the evolution of the electron temperature and density profiles are alike in the two heating schemes, the radial electric field and density turbulence profiles evolve differently, ending up in a higher density limit and higher energy content in plasmas heated with counter-NBI (NBI2). Besides, some differences in the plasma radiation profiles are detected whose evolution is presently being studied. | ||
The experimental characterization of the beams indicates that both present similar re-ionization losses and transmission [1], while NBI heating simulations performed using ASCOT [2] show more direct ion losses using co-NBI heating and better efficiency using counter-NBI for the same plasma profiles. | The experimental characterization of the beams indicates that both present similar re-ionization losses and transmission [1], while NBI heating simulations performed using ASCOT [2, 3] show more direct ion losses using co-NBI heating and better efficiency using counter-NBI for the same plasma profiles. | ||
Previous experiments indicate that the differences become more noticeable as the heating power increases. | Previous experiments indicate that the differences become more noticeable as the heating power increases. | ||
In this proposal we would like to proceed with the co- vs. counter-NBI comparison aiming at the identification of the relevant physical mechanisms responsible for the experimental observations. | In this proposal we would like to proceed with the co- vs. counter-NBI comparison aiming at the identification of the relevant physical mechanisms responsible for the experimental observations. | ||
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[1] M. Liniers et al., FED 123, 259 (2017) | [1] M. Liniers et al., FED 123, 259 (2017) | ||
[2] | [2] J.Guasp, M.Liniers, Informe técnico 761 "Comportamiento de las pérdidas instantáneas y retardadas en la inyección de neutros del TJ-II" | ||
[3] S.Mulas et al., 1st HPC fusion workshop 2020, ''Simulations of neutral beam injection in TJ-II stellarator using ASCOT5" | |||
== International or National funding project or entity == | == International or National funding project or entity == | ||