Observation of enhanced ion particle transport in mixed H/D isotope plasmas on JET

JET contributors

doi:10.1088/1741-4326/aac342

Observation of enhanced ion particle transport in mixed H/D isotope plasmas on JET

JET contributors

Research output: Contribution to journal › Article › peer-review

23 Scopus citations

Abstract

Particle transport in tokamak plasmas has been intensively studied in the past, particularly in relation to density peaking and the presence of anomalous inward particle convection in L- and H-modes. While in the L-mode case the presence of the anomalous inward pinch has previously been unambiguously demonstrated, particle transport in the H-mode was unclear. The main difficulty of such studies is that particle diffusion and convection could not be measured independently in steady-state conditions in the presence of a core particle flux. Therefore, it is usually not possible to separate the transport effect(inward convection), from the source effect (slow diffusion of particles introduced to the plasma core by neutral beam injection heating). In this work we describe experiments done on JET with mixtures of two hydrogenic isotopes: H and D. It is demonstrated that in the case of several ion species, convection and diffusion can be separated in a steady plasma without implementation of perturbative techniques such as gas puff modulation. Previous H-mode density peaking studies suggested that for this relatively high electron collisionality plasma scenario, the observed density gradient is mostly driven by particle source and low particle diffusivity D < 0.5 ∗ χ _eff. Transport coefficients derived from observation of the isotope profiles in the new experiments far exceed that value - ion particle diffusion is found to be as high as D 2 ∗ χ _eff, combined with a strong inward convection. Apparent disagreement with previous findings was explained by significantly faster transport of ion components with respect to the electrons, which could not be observed in a single main ion species plasma. This conclusion is confirmed by quasilinear gyrokinetic simulations.

Original language	English
Article number	076022
Journal	Nuclear Fusion
Volume	58
Issue number	7
DOIs	https://doi.org/10.1088/1741-4326/aac342
State	Published - 4 Jun 2018
Externally published	Yes

Keywords

Particle transport
Tokamak
plasma

Access to Document

10.1088/1741-4326/aac342

Cite this

@article{fff76995b90c48f8bcef6cb7f9bd58ff,

title = "Observation of enhanced ion particle transport in mixed H/D isotope plasmas on JET",

abstract = "Particle transport in tokamak plasmas has been intensively studied in the past, particularly in relation to density peaking and the presence of anomalous inward particle convection in L- and H-modes. While in the L-mode case the presence of the anomalous inward pinch has previously been unambiguously demonstrated, particle transport in the H-mode was unclear. The main difficulty of such studies is that particle diffusion and convection could not be measured independently in steady-state conditions in the presence of a core particle flux. Therefore, it is usually not possible to separate the transport effect(inward convection), from the source effect (slow diffusion of particles introduced to the plasma core by neutral beam injection heating). In this work we describe experiments done on JET with mixtures of two hydrogenic isotopes: H and D. It is demonstrated that in the case of several ion species, convection and diffusion can be separated in a steady plasma without implementation of perturbative techniques such as gas puff modulation. Previous H-mode density peaking studies suggested that for this relatively high electron collisionality plasma scenario, the observed density gradient is mostly driven by particle source and low particle diffusivity D < 0.5 ∗ χ eff. Transport coefficients derived from observation of the isotope profiles in the new experiments far exceed that value - ion particle diffusion is found to be as high as D 2 ∗ χ eff, combined with a strong inward convection. Apparent disagreement with previous findings was explained by significantly faster transport of ion components with respect to the electrons, which could not be observed in a single main ion species plasma. This conclusion is confirmed by quasilinear gyrokinetic simulations.",

keywords = "Particle transport, Tokamak, plasma",

author = "{JET contributors} and M. Maslov and King, {D. B.} and E. Viezzer and Keeling, {D. L.} and C. Giroud and T. Tala and A. Salmi and M. Marin and J. Citrin and C. Bourdelle and Solano, {E. R.} and X. Litaudon and S. Abduallev and M. Abhangi and P. Abreu and M. Afzal and Aggarwal, {K. M.} and T. Ahlgren and Ahn, {J. H.} and L. Aho-Mantila and N. Aiba and M. Airila and R. Albanese and V. Aldred and D. Alegre and E. Alessi and P. Aleynikov and A. Alfier and A. Alkseev and M. Allinson and B. Alper and E. Alves and G. Ambrosino and R. Ambrosino and L. Amicucci and V. Amosov and Sund{\'e}n, {E. Andersson} and M. Angelone and M. Anghel and C. Angioni and L. Appel and C. Appelbee and P. Arena and M. Ariola and H. Arnichand and S. Arshad and A. Ash and N. Ashikawa and V. Aslanyan and Wiechec, {A. Baron}",

note = "Publisher Copyright: {\textcopyright} EURATOM 2018.",

year = "2018",

month = jun,

day = "4",

doi = "10.1088/1741-4326/aac342",

language = "英语",

volume = "58",

journal = "Nuclear Fusion",

issn = "0029-5515",

publisher = "IOP Publishing Ltd.",

number = "7",

}

TY - JOUR

T1 - Observation of enhanced ion particle transport in mixed H/D isotope plasmas on JET

AU - JET contributors

AU - Maslov, M.

AU - King, D. B.

AU - Viezzer, E.

AU - Keeling, D. L.

AU - Giroud, C.

AU - Tala, T.

AU - Salmi, A.

AU - Marin, M.

AU - Citrin, J.

AU - Bourdelle, C.

AU - Solano, E. R.

AU - Litaudon, X.

AU - Abduallev, S.

AU - Abhangi, M.

AU - Abreu, P.

AU - Afzal, M.

AU - Aggarwal, K. M.

AU - Ahlgren, T.

AU - Ahn, J. H.

AU - Aho-Mantila, L.

AU - Aiba, N.

AU - Airila, M.

AU - Albanese, R.

AU - Aldred, V.

AU - Alegre, D.

AU - Alessi, E.

AU - Aleynikov, P.

AU - Alfier, A.

AU - Alkseev, A.

AU - Allinson, M.

AU - Alper, B.

AU - Alves, E.

AU - Ambrosino, G.

AU - Ambrosino, R.

AU - Amicucci, L.

AU - Amosov, V.

AU - Sundén, E. Andersson

AU - Angelone, M.

AU - Anghel, M.

AU - Angioni, C.

AU - Appel, L.

AU - Appelbee, C.

AU - Arena, P.

AU - Ariola, M.

AU - Arnichand, H.

AU - Arshad, S.

AU - Ash, A.

AU - Ashikawa, N.

AU - Aslanyan, V.

AU - Wiechec, A. Baron

PY - 2018/6/4

Y1 - 2018/6/4

N2 - Particle transport in tokamak plasmas has been intensively studied in the past, particularly in relation to density peaking and the presence of anomalous inward particle convection in L- and H-modes. While in the L-mode case the presence of the anomalous inward pinch has previously been unambiguously demonstrated, particle transport in the H-mode was unclear. The main difficulty of such studies is that particle diffusion and convection could not be measured independently in steady-state conditions in the presence of a core particle flux. Therefore, it is usually not possible to separate the transport effect(inward convection), from the source effect (slow diffusion of particles introduced to the plasma core by neutral beam injection heating). In this work we describe experiments done on JET with mixtures of two hydrogenic isotopes: H and D. It is demonstrated that in the case of several ion species, convection and diffusion can be separated in a steady plasma without implementation of perturbative techniques such as gas puff modulation. Previous H-mode density peaking studies suggested that for this relatively high electron collisionality plasma scenario, the observed density gradient is mostly driven by particle source and low particle diffusivity D < 0.5 ∗ χ eff. Transport coefficients derived from observation of the isotope profiles in the new experiments far exceed that value - ion particle diffusion is found to be as high as D 2 ∗ χ eff, combined with a strong inward convection. Apparent disagreement with previous findings was explained by significantly faster transport of ion components with respect to the electrons, which could not be observed in a single main ion species plasma. This conclusion is confirmed by quasilinear gyrokinetic simulations.

AB - Particle transport in tokamak plasmas has been intensively studied in the past, particularly in relation to density peaking and the presence of anomalous inward particle convection in L- and H-modes. While in the L-mode case the presence of the anomalous inward pinch has previously been unambiguously demonstrated, particle transport in the H-mode was unclear. The main difficulty of such studies is that particle diffusion and convection could not be measured independently in steady-state conditions in the presence of a core particle flux. Therefore, it is usually not possible to separate the transport effect(inward convection), from the source effect (slow diffusion of particles introduced to the plasma core by neutral beam injection heating). In this work we describe experiments done on JET with mixtures of two hydrogenic isotopes: H and D. It is demonstrated that in the case of several ion species, convection and diffusion can be separated in a steady plasma without implementation of perturbative techniques such as gas puff modulation. Previous H-mode density peaking studies suggested that for this relatively high electron collisionality plasma scenario, the observed density gradient is mostly driven by particle source and low particle diffusivity D < 0.5 ∗ χ eff. Transport coefficients derived from observation of the isotope profiles in the new experiments far exceed that value - ion particle diffusion is found to be as high as D 2 ∗ χ eff, combined with a strong inward convection. Apparent disagreement with previous findings was explained by significantly faster transport of ion components with respect to the electrons, which could not be observed in a single main ion species plasma. This conclusion is confirmed by quasilinear gyrokinetic simulations.

KW - Particle transport

KW - Tokamak

KW - plasma

UR - http://www.scopus.com/inward/record.url?scp=85049826718&partnerID=8YFLogxK

U2 - 10.1088/1741-4326/aac342

DO - 10.1088/1741-4326/aac342

M3 - 文章

AN - SCOPUS:85049826718

SN - 0029-5515

VL - 58

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 7

M1 - 076022

ER -

Observation of enhanced ion particle transport in mixed H/D isotope plasmas on JET

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Cite this