Nonlinear decay of high-power microwaves into trapped modes in inhomogeneous plasma

A. Tancetti; S. K. Nielsen; J. Rasmussen; E. Z. Gusakov; A. Yu Popov; D. Moseev; T. Stange; M. G. Senstius; C. Killer; M. Vecséi; T. Jensen; M. Zanini; I. Abramovic; M. Stejner; G. Anda; D. Dunai; S. Zoletnik; H. P. Laqua

doi:10.1088/1741-4326/ac5d61

Nonlinear decay of high-power microwaves into trapped modes in inhomogeneous plasma

A. Tancetti^*, S. K. Nielsen, J. Rasmussen, E. Z. Gusakov, A. Yu Popov, D. Moseev, T. Stange, M. G. Senstius, C. Killer, M. Vecséi, T. Jensen, M. Zanini, I. Abramovic, M. Stejner, G. Anda, D. Dunai, S. Zoletnik, H. P. Laqua

^*Corresponding author for this work

Research output: Contribution to journal › Journal article › Research › peer-review

Abstract

We present novel experimental evidence of parametric decay instability of microwave beams in the plasma edge of the Wendelstein 7-X stellarator. We propose that the instability is sustained by trapping of only one daughter wave in the non-monotonic density profile measured with high spatial resolution within a stationary magnetic island. The power levels and spectral shapes of the detected microwave signal are reproduced by numerical modelling and a theoretical power threshold is predicted around 300 kW, comparable with observations. We predict a fraction of power drained by daughter waves around 4% in the experiments, potentially increasing above 50% for more hollow edge density profiles. Such absorption levels could significantly reduce the efficiency of the microwave heating and current-drive system in tokamaks and stellarators.

Original language	English
Article number	074003
Journal	Nuclear Fusion
Volume	62
Issue number	7
Number of pages	6
ISSN	0029-5515
DOIs	https://doi.org/10.1088/1741-4326/ac5d61
Publication status	Published - 2022

Keywords

Collective Thomson scattering
Electron cyclotron resonance heating
Ion Bernstein waves
Parametric decay instability
Upper hybrid wave
Wendelstein 7-X stellarator

Access to Document

10.1088/1741-4326/ac5d61

OpenUrl availability

Full text

Embargoed Document

fulltext
Accepted author manuscript, 619 KB
Embargo ends: 28/04/2024

Cite this

Tancetti, A., Nielsen, S. K., Rasmussen, J., Gusakov, E. Z., Popov, A. Y., Moseev, D., Stange, T., Senstius, M. G., Killer, C., Vecséi, M., Jensen, T., Zanini, M., Abramovic, I., Stejner, M., Anda, G., Dunai, D., Zoletnik, S., & Laqua, H. P. (2022). Nonlinear decay of high-power microwaves into trapped modes in inhomogeneous plasma. Nuclear Fusion, 62(7), [074003]. https://doi.org/10.1088/1741-4326/ac5d61

@article{a430d22310df4755aaa2e63dfa6d1cdf,

title = "Nonlinear decay of high-power microwaves into trapped modes in inhomogeneous plasma",

abstract = "We present novel experimental evidence of parametric decay instability of microwave beams in the plasma edge of the Wendelstein 7-X stellarator. We propose that the instability is sustained by trapping of only one daughter wave in the non-monotonic density profile measured with high spatial resolution within a stationary magnetic island. The power levels and spectral shapes of the detected microwave signal are reproduced by numerical modelling and a theoretical power threshold is predicted around 300 kW, comparable with observations. We predict a fraction of power drained by daughter waves around 4% in the experiments, potentially increasing above 50% for more hollow edge density profiles. Such absorption levels could significantly reduce the efficiency of the microwave heating and current-drive system in tokamaks and stellarators.",

keywords = "Collective Thomson scattering, Electron cyclotron resonance heating, Ion Bernstein waves, Parametric decay instability, Upper hybrid wave, Wendelstein 7-X stellarator",

author = "A. Tancetti and Nielsen, {S. K.} and J. Rasmussen and Gusakov, {E. Z.} and Popov, {A. Yu} and D. Moseev and T. Stange and Senstius, {M. G.} and C. Killer and M. Vecs{\'e}i and T. Jensen and M. Zanini and I. Abramovic and M. Stejner and G. Anda and D. Dunai and S. Zoletnik and Laqua, {H. P.}",

note = "Publisher Copyright: {\textcopyright} EURATOM 2022.",

year = "2022",

doi = "10.1088/1741-4326/ac5d61",

language = "English",

volume = "62",

journal = "Nuclear Fusion",

issn = "0029-5515",

publisher = "IOP Publishing",

number = "7",

}

Tancetti, A, Nielsen, SK , Rasmussen, J, Gusakov, EZ, Popov, AY, Moseev, D, Stange, T, Senstius, MG, Killer, C, Vecséi, M, Jensen, T, Zanini, M, Abramovic, I, Stejner, M, Anda, G, Dunai, D, Zoletnik, S & Laqua, HP 2022, 'Nonlinear decay of high-power microwaves into trapped modes in inhomogeneous plasma', Nuclear Fusion, vol. 62, no. 7, 074003. https://doi.org/10.1088/1741-4326/ac5d61

TY - JOUR

T1 - Nonlinear decay of high-power microwaves into trapped modes in inhomogeneous plasma

AU - Tancetti, A.

AU - Nielsen, S. K.

AU - Rasmussen, J.

AU - Gusakov, E. Z.

AU - Popov, A. Yu

AU - Moseev, D.

AU - Stange, T.

AU - Senstius, M. G.

AU - Killer, C.

AU - Vecséi, M.

AU - Jensen, T.

AU - Zanini, M.

AU - Abramovic, I.

AU - Stejner, M.

AU - Anda, G.

AU - Dunai, D.

AU - Zoletnik, S.

AU - Laqua, H. P.

PY - 2022

Y1 - 2022

N2 - We present novel experimental evidence of parametric decay instability of microwave beams in the plasma edge of the Wendelstein 7-X stellarator. We propose that the instability is sustained by trapping of only one daughter wave in the non-monotonic density profile measured with high spatial resolution within a stationary magnetic island. The power levels and spectral shapes of the detected microwave signal are reproduced by numerical modelling and a theoretical power threshold is predicted around 300 kW, comparable with observations. We predict a fraction of power drained by daughter waves around 4% in the experiments, potentially increasing above 50% for more hollow edge density profiles. Such absorption levels could significantly reduce the efficiency of the microwave heating and current-drive system in tokamaks and stellarators.

AB - We present novel experimental evidence of parametric decay instability of microwave beams in the plasma edge of the Wendelstein 7-X stellarator. We propose that the instability is sustained by trapping of only one daughter wave in the non-monotonic density profile measured with high spatial resolution within a stationary magnetic island. The power levels and spectral shapes of the detected microwave signal are reproduced by numerical modelling and a theoretical power threshold is predicted around 300 kW, comparable with observations. We predict a fraction of power drained by daughter waves around 4% in the experiments, potentially increasing above 50% for more hollow edge density profiles. Such absorption levels could significantly reduce the efficiency of the microwave heating and current-drive system in tokamaks and stellarators.

KW - Collective Thomson scattering

KW - Electron cyclotron resonance heating

KW - Ion Bernstein waves

KW - Parametric decay instability

KW - Upper hybrid wave

KW - Wendelstein 7-X stellarator

U2 - 10.1088/1741-4326/ac5d61

DO - 10.1088/1741-4326/ac5d61

M3 - Journal article

AN - SCOPUS:85129433166

VL - 62

JO - Nuclear Fusion

JF - Nuclear Fusion

SN - 0029-5515

IS - 7

M1 - 074003

ER -

Nonlinear decay of high-power microwaves into trapped modes in inhomogeneous plasma

Abstract

Keywords

Access to Document

OpenUrl availability

Embargoed Document

Fingerprint

Cite this