Scaling laws for the cutoff wavenumber of the short-wavelength ion-temperature-gradient mode in a Z-pinch

Fuente: arXiv
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Autores principales: Gupta, O., Barnes, M., Parra, F. I., Podavini, L., Zocco, A., Adkins, T., Ivanov, P. G.
Formato: Preprint
Publicado: 2026
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author Gupta, O.
Barnes, M.
Parra, F. I.
Podavini, L.
Zocco, A.
Adkins, T.
Ivanov, P. G.
author_facet Gupta, O.
Barnes, M.
Parra, F. I.
Podavini, L.
Zocco, A.
Adkins, T.
Ivanov, P. G.
contents We use a heuristic fluid model to predict the dependence of the cutoff wave number for the short-wavelength ion temperature gradient (SWITG) mode on ion density gradient, ion temperature gradient (ITG) and ion-electron temperature ratio. In particular, we predict that the cutoff wave number increases linearly with increasing ITG for sufficiently large values of the ITG. Direct numerical solutions of the gyrokinetic dispersion relation using a purpose-built solver confirm the predicted scalings at large ITG values and find a weaker power-law scaling for intermediate ITG values. Combining these wave number scalings with a simple diffusive estimate for turbulent fluxes produces a scaling prediction for the ITG heat flux in SWITG-driven turbulence. Applying the critical balance conjecture additionally provides scalings for the aspect ratio of the SWITG turbulent eddies.
format Preprint
id arxiv_https___arxiv_org_abs_2602_09827
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Scaling laws for the cutoff wavenumber of the short-wavelength ion-temperature-gradient mode in a Z-pinch
Gupta, O.
Barnes, M.
Parra, F. I.
Podavini, L.
Zocco, A.
Adkins, T.
Ivanov, P. G.
Plasma Physics
We use a heuristic fluid model to predict the dependence of the cutoff wave number for the short-wavelength ion temperature gradient (SWITG) mode on ion density gradient, ion temperature gradient (ITG) and ion-electron temperature ratio. In particular, we predict that the cutoff wave number increases linearly with increasing ITG for sufficiently large values of the ITG. Direct numerical solutions of the gyrokinetic dispersion relation using a purpose-built solver confirm the predicted scalings at large ITG values and find a weaker power-law scaling for intermediate ITG values. Combining these wave number scalings with a simple diffusive estimate for turbulent fluxes produces a scaling prediction for the ITG heat flux in SWITG-driven turbulence. Applying the critical balance conjecture additionally provides scalings for the aspect ratio of the SWITG turbulent eddies.
title Scaling laws for the cutoff wavenumber of the short-wavelength ion-temperature-gradient mode in a Z-pinch
topic Plasma Physics
url https://arxiv.org/abs/2602.09827