The Divertor Tokamak Test (DTT) [1],[2] is a superconducting device under construction in Frascati, Italy. DTT was proposed to assess the performance of a conventional ITER divertor and address the power exhaust issue that will affect future fusion devices as DEMO. DTT will be equipped with three auxiliary heating systems, including a Neutral Beam Injection (NBI) system. DTT NBI is a high-energy and high-power neutral beam system (ENBI = 250-510 keV, PNBI <= 10 MW) that generates a population of suprathermal particles, known as Energetic Particles (EPs). EP confinement is crucial to improve plasma performances and avoid EP losses to the machine first wall. In this contribution, we characterize the beam-plasma interaction in axisymmetric magnetic field for different planned DTT plasma scenarios. The aim of the present investigation is to explore beam EP confinement in DTT plasmas, extending previous analyses [3] of the reference plasma scenario [4] to configurations at reduced toroidal magnetic field or current, taking into account the possibility of reducing NBI energy and power. The orbit-following Monte Carlo ASCOT suite of codes [5] is used. In particular, BBNBI [6] is used to evaluate the fraction of shine-through losses, i.e. beam particles lost to the first wall before ionization occurs. Through BBNBI we also obtain the information on newly-born fast ions required to populate the topological map built in the Constant of Motion (CoM) phase space [7]. This topological map is used to predict initial EP orbits and prompt losses, i.e. losses happening before collisions with background plasma occur. The ASCOT code is instead used to simulate the full slowing down collisional process and in order to gather information about EP distribution functions, beam contribution to the plasma in terms of power, current and momentum, and possible additional loss channels, e.g. orbit losses. Predictive beam-plasma interaction modelling is essential to explore the use of the NBI system on DTT plasmas, defining its operability. This contribution presents a further step to optimize future DTT operations by contributing to the understanding of beam EP behavior in DTT.
NBI energetic particle confinement and orbit characterization for Divertor Tokamak Test plasma scenarios
Vincenzi P;
2023
Abstract
The Divertor Tokamak Test (DTT) [1],[2] is a superconducting device under construction in Frascati, Italy. DTT was proposed to assess the performance of a conventional ITER divertor and address the power exhaust issue that will affect future fusion devices as DEMO. DTT will be equipped with three auxiliary heating systems, including a Neutral Beam Injection (NBI) system. DTT NBI is a high-energy and high-power neutral beam system (ENBI = 250-510 keV, PNBI <= 10 MW) that generates a population of suprathermal particles, known as Energetic Particles (EPs). EP confinement is crucial to improve plasma performances and avoid EP losses to the machine first wall. In this contribution, we characterize the beam-plasma interaction in axisymmetric magnetic field for different planned DTT plasma scenarios. The aim of the present investigation is to explore beam EP confinement in DTT plasmas, extending previous analyses [3] of the reference plasma scenario [4] to configurations at reduced toroidal magnetic field or current, taking into account the possibility of reducing NBI energy and power. The orbit-following Monte Carlo ASCOT suite of codes [5] is used. In particular, BBNBI [6] is used to evaluate the fraction of shine-through losses, i.e. beam particles lost to the first wall before ionization occurs. Through BBNBI we also obtain the information on newly-born fast ions required to populate the topological map built in the Constant of Motion (CoM) phase space [7]. This topological map is used to predict initial EP orbits and prompt losses, i.e. losses happening before collisions with background plasma occur. The ASCOT code is instead used to simulate the full slowing down collisional process and in order to gather information about EP distribution functions, beam contribution to the plasma in terms of power, current and momentum, and possible additional loss channels, e.g. orbit losses. Predictive beam-plasma interaction modelling is essential to explore the use of the NBI system on DTT plasmas, defining its operability. This contribution presents a further step to optimize future DTT operations by contributing to the understanding of beam EP behavior in DTT.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
