Diagnostic of fast-ion energy spectra and densities in magnetized plasmas

Mirko Salewski*, M. Nocente, Birgitte Madsen, I. Abramovic, G. Gorini, A. S. Jacobsen, V. Kiptily, Søren Bang Korsholm, Dmitry Moseev, Stefan Kragh Nielsen, Andreas Feldt Lomholt Poulsen, Jesper Rasmussen, M. Tardocchi, B. Geiger, J. Eriksson, ASDEX Upgrade Team, EUROfusion MST1 Team

*Corresponding author for this work

Research output: Contribution to journalConference articleResearchpeer-review

Abstract

The measurement of the energy spectra and densities of α-particles and other fast ions are part of the ITER measurement requirements, highlighting the importance of energy-resolved energetic-particle measurements for the mission of ITER. However, it has been found in recent years that the velocity-space interrogation regions of the foreseen energetic-particle diagnostics do not allow these measurements directly. We will demonstrate this for γ-ray spectroscopy (GRS), collective Thomson scattering (CTS), neutron emission spectroscopy and fast-ion Dα spectroscopy by invoking energy and momentum conservation in each case, highlighting analogies and differences between the different diagnostic velocity-space sensitivities. Nevertheless, energy spectra and densities can be inferred by velocity-space tomography which we demonstrate using measurements at JET and ASDEX Upgrade. The measured energy spectra agree well with corresponding simulations. At ITER, α-particle energy spectra and densities can be inferred for energies larger than 1.7 MeV by velocity-space tomography based on GRS and CTS. Further, assuming isotropy of the α-particles in velocity space, their energy spectra and densities can be inferred by 1D inversion of spectral single-detector measurements down to about 300 keV by CTS. The α-particle density can also be found by fitting a model to the CTS measurements assuming the α-particle distribution to be an isotropic slowing-down distribution.
Original languageEnglish
JournalJournal of Instrumentation
Volume14
Number of pages17
ISSN1748-0221
DOIs
Publication statusPublished - 2019
Event5th International Conference Frontiers in Diagnostcs Technologies - Rome, Italy
Duration: 3 Oct 20185 Oct 2018

Conference

Conference5th International Conference Frontiers in Diagnostcs Technologies
CountryItaly
CityRome
Period03/10/201805/10/2018

Keywords

  • Nuclear instruments and methods for hot plasma diagnostics
  • Computerized Tomography (TG)
  • Computed Radiography (CR)

Cite this

Salewski, Mirko ; Nocente, M. ; Madsen, Birgitte ; Abramovic, I. ; Gorini, G. ; Jacobsen, A. S. ; Kiptily, V. ; Korsholm, Søren Bang ; Moseev, Dmitry ; Nielsen, Stefan Kragh ; Poulsen, Andreas Feldt Lomholt ; Rasmussen, Jesper ; Tardocchi, M. ; Geiger, B. ; Eriksson, J. ; ASDEX Upgrade Team ; EUROfusion MST1 Team. / Diagnostic of fast-ion energy spectra and densities in magnetized plasmas. In: Journal of Instrumentation. 2019 ; Vol. 14.
@inproceedings{d537f6f33b9a49f6a03706359623c282,
title = "Diagnostic of fast-ion energy spectra and densities in magnetized plasmas",
abstract = "The measurement of the energy spectra and densities of α-particles and other fast ions are part of the ITER measurement requirements, highlighting the importance of energy-resolved energetic-particle measurements for the mission of ITER. However, it has been found in recent years that the velocity-space interrogation regions of the foreseen energetic-particle diagnostics do not allow these measurements directly. We will demonstrate this for γ-ray spectroscopy (GRS), collective Thomson scattering (CTS), neutron emission spectroscopy and fast-ion Dα spectroscopy by invoking energy and momentum conservation in each case, highlighting analogies and differences between the different diagnostic velocity-space sensitivities. Nevertheless, energy spectra and densities can be inferred by velocity-space tomography which we demonstrate using measurements at JET and ASDEX Upgrade. The measured energy spectra agree well with corresponding simulations. At ITER, α-particle energy spectra and densities can be inferred for energies larger than 1.7 MeV by velocity-space tomography based on GRS and CTS. Further, assuming isotropy of the α-particles in velocity space, their energy spectra and densities can be inferred by 1D inversion of spectral single-detector measurements down to about 300 keV by CTS. The α-particle density can also be found by fitting a model to the CTS measurements assuming the α-particle distribution to be an isotropic slowing-down distribution.",
keywords = "Nuclear instruments and methods for hot plasma diagnostics, Computerized Tomography (TG), Computed Radiography (CR)",
author = "Mirko Salewski and M. Nocente and Birgitte Madsen and I. Abramovic and G. Gorini and Jacobsen, {A. S.} and V. Kiptily and Korsholm, {S{\o}ren Bang} and Dmitry Moseev and Nielsen, {Stefan Kragh} and Poulsen, {Andreas Feldt Lomholt} and Jesper Rasmussen and M. Tardocchi and B. Geiger and J. Eriksson and {ASDEX Upgrade Team} and {EUROfusion MST1 Team}",
year = "2019",
doi = "10.1088/1748-0221/14/05/C05019",
language = "English",
volume = "14",
journal = "Journal of Instrumentation",
issn = "1748-0221",
publisher = "IOP Publishing",

}

Salewski, M, Nocente, M, Madsen, B, Abramovic, I, Gorini, G, Jacobsen, AS, Kiptily, V, Korsholm, SB, Moseev, D, Nielsen, SK, Poulsen, AFL, Rasmussen, J, Tardocchi, M, Geiger, B, Eriksson, J, ASDEX Upgrade Team & EUROfusion MST1 Team 2019, 'Diagnostic of fast-ion energy spectra and densities in magnetized plasmas', Journal of Instrumentation, vol. 14. https://doi.org/10.1088/1748-0221/14/05/C05019

Diagnostic of fast-ion energy spectra and densities in magnetized plasmas. / Salewski, Mirko; Nocente, M.; Madsen, Birgitte; Abramovic, I.; Gorini, G.; Jacobsen, A. S.; Kiptily, V.; Korsholm, Søren Bang; Moseev, Dmitry; Nielsen, Stefan Kragh; Poulsen, Andreas Feldt Lomholt; Rasmussen, Jesper; Tardocchi, M.; Geiger, B.; Eriksson, J.; ASDEX Upgrade Team; EUROfusion MST1 Team.

In: Journal of Instrumentation, Vol. 14, 2019.

Research output: Contribution to journalConference articleResearchpeer-review

TY - GEN

T1 - Diagnostic of fast-ion energy spectra and densities in magnetized plasmas

AU - Salewski, Mirko

AU - Nocente, M.

AU - Madsen, Birgitte

AU - Abramovic, I.

AU - Gorini, G.

AU - Jacobsen, A. S.

AU - Kiptily, V.

AU - Korsholm, Søren Bang

AU - Moseev, Dmitry

AU - Nielsen, Stefan Kragh

AU - Poulsen, Andreas Feldt Lomholt

AU - Rasmussen, Jesper

AU - Tardocchi, M.

AU - Geiger, B.

AU - Eriksson, J.

AU - ASDEX Upgrade Team

AU - EUROfusion MST1 Team

PY - 2019

Y1 - 2019

N2 - The measurement of the energy spectra and densities of α-particles and other fast ions are part of the ITER measurement requirements, highlighting the importance of energy-resolved energetic-particle measurements for the mission of ITER. However, it has been found in recent years that the velocity-space interrogation regions of the foreseen energetic-particle diagnostics do not allow these measurements directly. We will demonstrate this for γ-ray spectroscopy (GRS), collective Thomson scattering (CTS), neutron emission spectroscopy and fast-ion Dα spectroscopy by invoking energy and momentum conservation in each case, highlighting analogies and differences between the different diagnostic velocity-space sensitivities. Nevertheless, energy spectra and densities can be inferred by velocity-space tomography which we demonstrate using measurements at JET and ASDEX Upgrade. The measured energy spectra agree well with corresponding simulations. At ITER, α-particle energy spectra and densities can be inferred for energies larger than 1.7 MeV by velocity-space tomography based on GRS and CTS. Further, assuming isotropy of the α-particles in velocity space, their energy spectra and densities can be inferred by 1D inversion of spectral single-detector measurements down to about 300 keV by CTS. The α-particle density can also be found by fitting a model to the CTS measurements assuming the α-particle distribution to be an isotropic slowing-down distribution.

AB - The measurement of the energy spectra and densities of α-particles and other fast ions are part of the ITER measurement requirements, highlighting the importance of energy-resolved energetic-particle measurements for the mission of ITER. However, it has been found in recent years that the velocity-space interrogation regions of the foreseen energetic-particle diagnostics do not allow these measurements directly. We will demonstrate this for γ-ray spectroscopy (GRS), collective Thomson scattering (CTS), neutron emission spectroscopy and fast-ion Dα spectroscopy by invoking energy and momentum conservation in each case, highlighting analogies and differences between the different diagnostic velocity-space sensitivities. Nevertheless, energy spectra and densities can be inferred by velocity-space tomography which we demonstrate using measurements at JET and ASDEX Upgrade. The measured energy spectra agree well with corresponding simulations. At ITER, α-particle energy spectra and densities can be inferred for energies larger than 1.7 MeV by velocity-space tomography based on GRS and CTS. Further, assuming isotropy of the α-particles in velocity space, their energy spectra and densities can be inferred by 1D inversion of spectral single-detector measurements down to about 300 keV by CTS. The α-particle density can also be found by fitting a model to the CTS measurements assuming the α-particle distribution to be an isotropic slowing-down distribution.

KW - Nuclear instruments and methods for hot plasma diagnostics

KW - Computerized Tomography (TG)

KW - Computed Radiography (CR)

U2 - 10.1088/1748-0221/14/05/C05019

DO - 10.1088/1748-0221/14/05/C05019

M3 - Conference article

VL - 14

JO - Journal of Instrumentation

JF - Journal of Instrumentation

SN - 1748-0221

ER -