ASDEX Upgrade

About: ASDEX Upgrade is a research topic. Over the lifetime, 2261 publications have been published within this topic receiving 39557 citations.

Scaling of the tokamak near the scrape-off layer H-mode power width and implications for ITER

Abstract: A multi-machine database for the H-mode scrape-off layer power fall-off length, λq in JET, DIII-D, ASDEX Upgrade, C-Mod, NSTX and MAST has been assembled under the auspices of the International Tokamak Physics Activity Regression inside the database finds that the most important scaling parameter is the poloidal magnetic field (or equivalently the plasma current), with λq decreasing linearly with increasing Bpol For the conventional aspect ratio tokamaks, the regression finds , yielding λq,ITER 1 mm for the baseline inductive H-mode burning plasma scenario at Ip = 15 MA The experimental divertor target heat flux profile data, from which λq is derived, also yield a divertor power spreading factor (S) which, together with λq, allows an integral power decay length on the target to be estimated There are no differences in the λq scaling obtained from all-metal or carbon dominated machines and the inclusion of spherical tokamaks has no significant influence on the regression parameters Comparison of the measured λq with the values expected from a recently published heuristic drift based model shows satisfactory agreement for all tokamaks

First observation of edge localized modes mitigation with resonant and nonresonant magnetic perturbations in ASDEX Upgrade.

Abstract: First experiments with nonaxisymmetric magnetic perturbations, toroidal mode number n=2, produced by newly installed in-vessel saddle coils in the ASDEX Upgrade tokamak show significant reduction of plasma energy loss and peak divertor power load associated with type-I edge localized modes (ELMs) in high-confinement mode plasmas. ELM mitigation is observed above an edge density threshold and is obtained both with magnetic perturbations that are resonant and not resonant with the edge safety factor profile. Compared with unperturbed type-I ELMy reference plasmas, plasmas with mitigated ELMs show similar confinement, similar plasma density, and lower tungsten impurity concentration.

Overview of the RF source development programme at IPP Garching

Abstract: The development of a large-area RF source for negative hydrogen ions, an official EFDA task agreement, is aiming at demonstrating ITER-relevant ion source parameters. This implies a current density of 200?A?m?2 accelerated D? ions at a source filling pressure of ?0.3?Pa and an electron-to-ion ratio of ?1 from an extraction area similar to the positive-ion based sources at JET and ASDEX Upgrade and for pulse lengths of up to 1?h. The work is progressing along three lines in parallel: (i) optimization of current densities at low pressure and electron/ion ratio, utilizing small extraction areas (<0.01?m2) and short pulses (<6?s), in this parameter range the ITER requirements are met or even exceeded; (ii) investigation on extended extraction areas (<0.03?m2) and pulse lengths of up to 3600?s and (iii) investigation of a size-scaling on a half-size ITER plasma source. Three different test beds are being used to carry out these investigations in parallel. An extensive diagnostic and modelling programme accompanies the activities. The paper discusses the recent achievements and the status in these three areas of development.