-
UKAEA-CCFE-PR(25)2712024
We detail here a semi-analytical model for the pellet rocket effect, which describes the acceleration of pellets in a fusion plasma due to asymmetries in the heat flux reaching the pellet surface and the corresponding ablation rate. This effect was shown in experiments to significantly modify the pellet trajectory, and projections for reactor sc…
-
UKAEA-CCFE-PR(25)2702024
Pellets of frozen material travelling into a magnetically confined fusion plasma are accelerated by the so-called pellet rocket effect. The non-uniform plasma heats the pellet ablation cloud asymmetrically, producing pressure-driven, rocket-like propulsion of the pellet. We present a semi-analytical model of this process by perturbing a spherica…
-
UKAEA-STEP-PR(24)182024
This paper presents a comprehensive overview of the preliminary divertor design and plasma exhaust scenario for the reactor-class Spherical Tokamak for Energy Production (STEP) project. Due to the smaller size of the machine, with a major radius less than half that of most DEMO concepts, the current design features a double-null divertor geometr…
-
UKAEA-CCFE-PR(24)2092024
This study systematically explores the parameter space of disruption mitigation through shattered pellet injection in ITER with a focus on runaway electron dynamics, using the disruption modelling tool Dream. The physics fidelity is considerably increased compared to previous studies, by e.g., using realistic magnetic geometry, resistive wall confi…
-
UKAEA-CCFE-PR(24)2082024
Microinstabilities drive turbulent fluctuations in inhomogeneous, magnetized plasmas. In the context of magnetic confinement fusion devices, this leads to an enhanced transport of particles, momentum, and energy, thereby degrading confinement. In this work, we elaborate on the application of the adjoint method to efficiently determine the variation…
-
UKAEA-STEP-PR(25)282023
Generation of Runaway Electrons (REs) during plasma disruptions, and their impact on plasma facing components, is of great concern for ITER and future reactors based on the tokamak concept. Current STEP (Spherical Tokamak for Energy Production) concept design flat top operating point features a plasma current higher than 20 MA and thus any plasm…
-
UKAEA-CCFE-PR(25)2642023
Advances in edge and scrape-off layer diagnostics have shown that often the ion temperature is higher than the electron temperature in scrape-off layer filaments. We have therefore extended the STORM model beyond the cold ion limit commonly used, to include hot ion effects. We find that filaments are both faster and more coherent than in a cold …
-
UKAEA-STEP-PR(24)192023
SOLPS-ITER simulations performed on STEP CDN geometry with Ar, varying D2 fuelling location Fuelling location can be an actuator for impurity compression/enrichment Inner-midplane (IMP) fuelling enhanced Ar compression/enrichment by 1) driving main plasma outflow 2) increasing collision frequency and 3) lowering upstream temperature PFR+IMP fuel…
-
UKAEA-STEP-PR(24)162023
The STEP (Spherical Tokamak for Energy Production) fusion programme aims to produce net energy as a prototype fusion energy plant in the 2040s. To find an exhaust solution which is compatible with the core, we need to achieve high impurity enrichment. In this study, we investigated the impact of deuterium gas puff location on impurity enrichme…
-
UKAEA-STEP-CP(23)122023
In order to achieve a compatible solution between the divertors and the core, SOLPS-ITER simulations were performed on STEP (Spherical Tokamak for Energy Production) connected double-null geometry to investigate the possibility of using deuterium (D) fuelling puff locations as an actuator for divertor argon (Ar) retention. Significant reduction of …
Showing 1 - 10 of 41 UKAEA Paper Results