Overview of the Fusion Science Activity in the RFX-mod Device towards RFX-mod2

Autor: Zuin M., RFX-mod team
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: The 1st International Conference on Innovative Fusion Approaches, Xi'an, China, May 26-28, 2019
info:cnr-pdr/source/autori:Zuin M.; RFX-mod team/congresso_nome:The 1st International Conference on Innovative Fusion Approaches/congresso_luogo:Xi'an, China/congresso_data:May 26-28, 2019/anno:2019/pagina_da:/pagina_a:/intervallo_pagine
Popis: The Reversed Field Pinch (RFP) is a low magnetic field configuration for the confinement of thermonuclear plasmas. It exploits the pinch effect due to a current flowing in a plasma embedded in the toroidal magnetic field, which is one order of magnitude smaller than in a tokamak. It thus represents a non-disruptive, ohmically heated approach to magnetic fusion, based on self-organization and technological simplicity. This talk presents recent advancements on the RFP physics obtained in the RFX-mod device, and the perspectives of the configuration as a viable alternative to magnetic fusion. RFX-mod allowed to perform experiments in regimes with plasma current levels up to 2 MA, thanks to its MHD active control system [1]. Experiments have shown that improved confinement performances are obtained when in the resonant part of the m=1 spectrum one dominant Tearing Mode is much higher than the other secondary ones (Quasi Single Helicity states) [2]. Tearing Modes play a crucial role in determining energy and particle transport. The interesting behavior of fast particles in the RFP will be shown to be connected to the spontaneous enhancement of neutron yields influenced by the MHD activity of the RFP plasmas. A positive isotope effect has been found in helical RFP plasmas, as well as the natural tendency of strong outward impurity convection [1]. Based on the present understanding of the interplay between Tearing modes and passive conductive boundaries in an RFP, an upgrade of RFX-mod machine has been designed, dubbed RFX-mod2 [3], now under implementation. The highly resistive Inconel vacuum vessel will be removed, first wall graphite tiles will be attached to the copper stabilizing shell and the stainless steel support structure will be modified in order to be vacuum tight. In RFX-mod2, the shell-plasma proximity will decrease from b/a=1.11 to b/a=1.04 and copper will be the continuous conducting structure nearest to the plasma, instead of Inconel. MHD non-linear simulations show that secondary Tearing Modes amplitude and the edge bulging due to their phase locking will be reduced; moreover, the plasma current threshold for Tearing Modes wall locking will also significantly increase with respect to that observed in RFX-mod [3].
Databáze: OpenAIRE
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