ECRad: An electron cyclotron radiation transport solver for advanced data analysis in thermal and non-thermal fusion plasmas

Denk, S. S.; Fischer, R.; Poli, E.; Maj, O.; Nielsen, S. K.; Rasmussen, Jesper; Stejner, M.; Willensdorfer, M.

doi:10.1016/j.cpc.2020.107175

Cited by 8 publications

(16 citation statements)

References 49 publications

(103 reference statements)

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“…soft X-ray measurements. To account for the possible refraction from the significant density perturbation at the edge, we employ the radiation transport forward model ECRad [6] where the geometry of the ECE system is included. We model the steep and the flat temperature profile scenarios of the discharge shown in figure 7.…”

Section: Refraction Effectsmentioning

confidence: 99%

“…The relative temperature fluctuation levels across the pedestal are assessed via the Correlation Electron Cyclotron Emission (CECE) instrument [5] covering the region of ρ pol = [0.85 − 1] while the standard ECE diagnostics is used for core-edge amplitude comparison and comparison to the modeling. EC Radiation transport is assessed with ECRad [6], a radiation transport code suitable for treating electron cyclotron emission with specifics of CECE and ECE diagnostics such as launching angles and IF bandwidth. Refraction is included in ECRad, allowing studies on the refractive effects on the core emission.…”

Section: Introductionmentioning

confidence: 99%

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Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius

Vanovac

Stober²,

Wolfrum³

et al. 2023

EPJ Web Conf.

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EDA H-mode is an ELM-free regime in which the edge quasi-coherent mode (QCM) replaces the ELMs. The estimated location of the quasi-coherent mode is in a partly optically thin region of steep gradients localized between ρpol = 0.96 -1. Relative fluctuations of radiation temperature between 15 and 80 kHz are about 7% with significant density contribution. In the electron cyclotron emission (ECE) channels with resonances in the plasma core, a mode with the same frequency as the quasi-coherent mode is measured. The peak amplitude of both core and edge modes matches the strongest electron temperature gradient in the core and the edge, respectively. The ECE core and edge signals are out of phase. The radiation transport forward model (ECRad) shows that the refraction explains the phase relation between the edge and the core ECE channels. The phase correlates with the sign of the core Te. The amplitude of the fluctuations in the core decreases with decreasing gradients, which is the trend seen in the experiment. The amplitude ratio of the core and edge fluctuation is a factor of five in the experiment; this ratio remains a factor of a hundred in the modeling.

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Section: Refraction Effectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius

Vanovac

Stober²,

Wolfrum³

et al. 2023

EPJ Web Conf.

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“…This was only observed for B t = 1.6 T and P 105GHz ≥ 2.5 MW. It has been checked with the radiation transport code ECRad [10] in combination with integrated data analysis [9] if this could be explained by shine-through effects due to limited optical thickness, as it was found to explain large radiation temperatures at the LFS edge of some plasmas. Still, no sensible T e -profiles were identified which would explain the data under these assumptions.…”

Section: Non-thermal (Non-linear) Effectsmentioning

confidence: 99%

Quantification of X3 absorption for ITER L-mode parameters in ASDEX Upgrade

Stober

Schubert²,

Schneider³

et al. 2023

EPJ Web Conf.

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For an early H-mode access in hydrogen, ITER considers operating at 1/3 of the full field using 170 GHz X-Mode for heating at the 3rd harmonic. The optical thickness for such a heating scheme depends on Te2. It is rather low in the ohmic phase (with Te about 1-2 keV), but reaches high single pass absorption for the strongly EC heated plasma with Te exceeding 10 keV. Launching ECRH into an ohmic plasma may trigger a boot-strap process on Te if the additional power absorption due to increasing Te exceeds the additional power losses due to increased transport (which often tends to increase with input power). In this contribution we present measurements of the X3 absorption for the parameter range relevant for ITER, i.e. ne 2 1019 m−3, Te 2 keV in order to back up theoretical estimates used for the modeling so far. In ASDEX Upgrade (AUG) such low densities cannot be reached in H-mode such that dominant heating with NBI is not an option. For moderate Te, it is also not an option to use X3 heating as main heating, due to the excessive stray radiation threatening in-vessel components. This dilemma is solved with the 2-frequency EC system of AUG. The main central heating is done with the lower frequency of 105 GHz at the 2nd harmonic and full single pass absorption. Up to 3.5 MW of ECRH are used at that frequency to vary Te. Two other gyrotrons are used at 140 GHz to probe the X3 interaction close to the plasma center with a sequence of short blips. The expected values of single pass absorption are calculated with TORBEAM and vary from 7% to 70%. Below 40% single pass absorption the non-absorbed power triggers an arc in the tile gaps of the inner heat shield which screens the thermo-couples from the incoming beam such that they cannot be used. Between 40% and 80% single pass absorption, the predictions and measurements agree within the uncertainty of the measurement, unless we have clear evidence for non-linear interactions, which are not described by TORBEAM and which are not expected in ITER, but are due to some specific experimental choices for an isolated subset of our results.

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“…Before the start of ITER operation and the availability of experimental data, synthetic diagnostics can be used to simulate measurements for given plasma parameters from predictive simulations and the configuration of each diagnostic system. For the identification of the L-H transition in ITER PFPO campaigns predictive simulations use advanced core and edge transport solvers like ASTRA [58], JINTRAC [59] and SOLPS-ITER [60,61] which results are stored in the IMAS Scenario Simulations database. These scenarios together with the synthetic diagnostics using the IMAS Machine Description database are used to produce simulated data to study the detection of the L-H transition.…”

Section: Imas/ida Integration (Ida)-r Fischermentioning

confidence: 99%

Summary report of the 4th IAEA Technical Meeting on Fusion Data Processing, Validation and Analysis (FDPVA)

Vicente

Mazon

et al. 2023

Nucl. Fusion

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The objective of the fourth Technical Meeting on Fusion Data Processing, Validation and Analysis was to provide a platform during which a set of topics relevant to fusion data processing, validation and analysis are discussed with the view of extrapolating needs to next step fusion devices such as ITER. The validation and analysis of experimental data obtained from diagnostics used to characterize fusion plasmas are crucial for a knowledge-based understanding of the physical processes governing the dynamics of these plasmas. This paper presents the recent progress and achievements in the domain of plasma diagnostics and synthetic diagnostics data analysis (including image processing, regression analysis, inverse problems, deep learning, machine learning, big data and physics-based models for control) reported at the meeting. The progress in these areas highlight trends observed in current major fusion confinement devices. A special focus is dedicated on data analysis requirements for ITER and DEMO with a particular attention paid to Artificial Intelligence for automatization and improving reliability of control processes.

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ECRad: An electron cyclotron radiation transport solver for advanced data analysis in thermal and non-thermal fusion plasmas

Cited by 8 publications

References 49 publications

Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius

Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius

Quantification of X3 absorption for ITER L-mode parameters in ASDEX Upgrade

Summary report of the 4th IAEA Technical Meeting on Fusion Data Processing, Validation and Analysis (FDPVA)

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