The behavior of tungsten impurity in fusion plasmas is one of the important issues to be studied to achieve high-temperature plasmas for fusion reactions since tungsten used as plasma-facing material is sputtered by plasma particles and is expected to reduce electron temperature due to large radiation power. Many studies have been done to examine atomic properties and spectral models for...
Light and metallic impurity identification in the 225-302 Å range from the SURVIE spectrometer in the WEST Tokamak
C. Desgranges(1), J.L. Schwob(2), P. Mandelbaum(3), R. Guirlet(1), Y. Boumendjel(1), O. Peyrusse(4), P. Manas(1), N. Fedorczak(1) and the WEST team(*)
(1) CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
(2) Racah Institute of Physics, The Hebrew University, 91904 Jerusalem,...
High-resolution x-ray crystal spectroscopy has been a workhorse on numerous tokamaks to measure the ion temperature and toroidal rotation profiles from the Doppler broadening and shift, respectively, of intrinsic or seeded impurity line radiation emission. SPARC will be a first-of-its-kind tokamak that will similarly employ this diagnostic. The unique high electron temperature and high neutron...
Understanding the basic plasma parameters of temperature and density, as well as their gradients in the scrape-off layer (SOL), is a topic critical for providing information about the performance of a divertor concept. The stellarator Wendelstein 7-X features a novel resonant island divertor with an adjustable rotational transform of ι = 2π (5/6, …, 5/4). In order to study the performance of...
High-Z materials such as tungsten and molybdenum have become leading solutions for plasma-facing materials. There are uncertainties in both erosion and transport of these elements requiring further research. The spectral emission of these high-Z species in combination with Collisional Radiative (CR) modeling can provide necessary information for plasma transport modeling. The Python program,...
Upper and lower graphite divertor in EAST tokamak have been updated to tungsten divertors in 2014 and 2021 respectively to investigate the tungsten divertor operation and to realize high-performance long pulse discharge. Therefore, studies on the tungsten behavior are crucially important for improving the plasma performance. For the purpose four fast-time-response [1-2] and four...
Most of the realistic kinetic calculations for tokamak plasmas require now to incorporate the effect of partially ionized high-Z elements, arising either from uncontrolled influxes of metallic impurities like tungsten in high input power regimes or from mitigation by massive gas injection of runaway electrons generated after plasma disruptions [1,2]. The usual electron-ion Fokker-Planck...
Abstract
The Doppler Shift Spectroscopy (DSS) diagnostics, since its inception as a diagnostics technique in Neutral Beam Injectors (NBI), has proved to be an indispensable tool for characterizing positive and negative ion beams and optimising the ion sources performance [1-2]. For positive ion beams, beam parameters such as beam energy, beam species mix, beam impurity fractions, beam...
Argon seeding in a tokamak has several benefits such as, achieving lower-H-mode thresholds [1, 2], reducing heatloads on plasma-periperals through radiative power dissipation at the plasma boundary [3] etc. Trace argon is also injected for diagnostic purposes [4, 5]. Nonetheless, argon accumulation in the core and its high radiation through line and continuum emissions result in confinement...
Atomic and molecular reaction dynamics must be understood and controlled to realize efficient conversion of diverted heat load from fusion core plasmas to radiation. However, the current knowledge of the reaction dynamics is still insufficient. For example, experimentally observed radiated power in divertors is not explained by even the most advanced simulation codes. The challenge in...
The collisional-radiative models (CRMs) play a significant role in the Monte-Carlo (MC) transport codes used for edge and divertor plasma in fusion relevant devices. In turn, the codes like the impurity transport code ERO [1] or the more oriented on the main plasma species EIRENE [2] are indispensable for the understanding of the interplay of various processes in edge and divertor plasmas of...
