Conveners
Mitigation
- Eric Nardon (CEA)
Mitigation
- Nicholas Eidietis (General Atomics)
Mitigation
- Nicholas Eidietis (General Atomics)
Mitigation
- long zeng
Mitigation
- long zeng
In support of the ITER DMS development, a highly flexible SPI system [[1], [2]] was installed at ASDEX Upgrade (AUG). It offers the unique opportunity to investigate the effect of different fragment size and velocity distributions — which were characterised beforehand in extensive laboratory tests — on the disruption behaviour. The triple barrel setup with independent freezing cells, injection...
Previous investigations on JET suggest thermal stored energy ($W_{th}$) is poorly mitigated by either Massive Gas Injection (MGI) or Shattered Pellet Injection (SPI) Disruption Mitigation Systems (DMS), when measured by weighted averages of bolometer channels. A contrasting investigation on ASDEX-Upgrade found that thermal energy is well mitigated with MGI. We investigate whether the apparent...
The ITER disruption mitigation system design using shattered pellet injection is reaching maturity, with the current leading strategy being a staggered pellet injection scheme. The first injection in this scheme uses pure hydrogen to reduce runaway electron (RE) generation by increasing plasma density and reducing electron temperature. The second injection consists of neon pellets to...
A series of experiments is underway to explore the effect of both self-excited and externally launched plasma waves on relativistic electrons (REs) across a wide range of geometries and plasma parameters. While O and X-mode waves are routinely used for heating and current-drive in tokamaks they are incapable of directly resonating with REs since their phase velocity is much greater than the...
Runaway electrons generated during tokamak disruptions are a major concern for the safe operation of future tokamaks. These energetic electrons can carry significant current and cause severe damage to a tokamak. Therefore, mitigating runaway electrons is essential for the safety and efficiency of fusion devices. Interaction of runaway electrons with waves is one of the potential mechanisms for...
The heat flux mitigation during the Thermal Quench (TQ) by the Shattered Pellet Injection (SPI) is one of the major elements of disruption mitigation strategy for ITER. It's efficiency greatly depends on the SPI and the target plasma parameters, and is ultimately characterised by the heat deposition on to the Plasma Facing Components (PFCs). To investigate such heat deposition, JOREK...
The disruption mitigation system (DMS) for ITER is based on the shattered pellet injection (SPI) technology. The principle of operation is to form cylindrical cm-sized cryogenic pellets and accelerate them to high speeds towards a shattering chamber, where the pellets disintegrate into a plume of fragments of different sizes and velocities, which then enter the plasma for the mitigation...
The ITER disruption mitigation support laboratory is part of the ITER Disruption Mitigation System (DMS) Task Force programme to establish the physics and technology basis for the ITER DMS. The laboratory is located at the HUN-REN Centre for Energy Research (CER), Budapest Hungary. The aims include production, launching and shattering of 28.5x57 mm (d x L) H, D, Ne and mixture pellets,...
Localized wall damage from post-disruption runaway electron (RE) wall impact is a significant concern for future large tokamaks. One possible method for reducing this wall damage in the event of an unavoidable RE-wall impact is massive injection of low-Z (H2 or D2) gas. This injection can have the effect of partially recombining the cold thermal background plasma, resulting in a greatly...
Runaway electrons of MeV and higher energies can dominate the plasma
current during ITER startup and the current quench phase of a major
disruption. The plasma regime spans from reasonably low-density and
high-temperature (startup) to high-density and low-temperature
(disruption mitigated by high-Z impurities), and somewhere in between
(disruption mitigation by low-Z injection). Here we...
Realizing tokamak power plants requires reducing the frequency and impact of disruptions sufficiently to accept them as a part of operations. SPARC is a high field tokamak [1] ($B_o=12.2$ T, $I_p=8.7$ MA) designed to demonstrate Q>1 and to explore divertor and disruption solutions for the ARC power plant. Significant disruption work is ongoing in hardware, software, operational planning, and...
Safe termination of the plasma discharge using injection of intense gas flows and macroparticles (pellets) is considered as the main system for preventing development of the runaway electron beams in tokamak-reactor (ITER) [1]. One of the main limitations in the use of these systems in large-scale tokamaks is the weak penetration of injected gas and particles into the central zones of the high...
