Abstract <p>The paper presents a numerical analysis of the possibility of performing local measurements of potential and plasma density fluctuations in the T-15MD tokamak using the Heavy Ion Beam Probe (HIBP) diagnostic. Four types of fluctuations are considered in the frequency range up to 500 kHz: Geodesic Acoustic Mode (GAM), Quasi-Coherent Mode (QCM), Tearing Mode (TM), and Alfvén eigenmode (AE). For each type of fluctuation, spatial measurement areas are defined for regimes with different values of average density <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\({{\bar {n}}_{e}}\)</EquationSource>  </InlineEquation> and toroidal magnetic field <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\({{B}_{T}}\)</EquationSource>  </InlineEquation>. Regimes with flat and peaked density profiles are considered. It is shown that high-Q fluctuations (GAM, AE, TM) can be measured in the peripheral region of the plasma <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\rho < 0.8\)</EquationSource>  </InlineEquation> up to density <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\({{\bar {n}}_{e}} \leqslant 7 \times {{10}^{{19}}}\;{{{\text{m}}}^{{ - 3}}}\)</EquationSource>  </InlineEquation>, while low-Q QCMs can be measured up to <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\({{\bar {n}}_{e}} \leqslant 5 \times {{10}^{{19}}}\;{{{\text{m}}}^{{ - 3}}}\)</EquationSource>  </InlineEquation>. In the plasma gradient region <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\rho = 0.5{-} 0.9\)</EquationSource>  </InlineEquation> the measurement of high-Q fluctuations is possible at a density of <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\({{\bar {n}}_{e}} \leqslant 5 \times {{10}^{{19}}}\;{{{\text{m}}}^{{ - 3}}}\)</EquationSource>  </InlineEquation>, and of the low-Q QCM at a density of <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\({{\bar {n}}_{e}} \leqslant 3 \times {{10}^{{19}}}\;{{{\text{m}}}^{{ - 3}}}\)</EquationSource>  </InlineEquation>.</p>

Spatial Areas of Potential and Density Fluctuation Measurements Using HIBP on the T-15MD Tokamak

期刊论文
发表日期：

2025年10月1日

查看全文

E. A. Vinitskiy,
L. G. Eliseev,
D. A. Shelukhin,
Y. M. Ammosov,
A. V. Melnikov

摘要

Abstract

The paper presents a numerical analysis of the possibility of performing local measurements of potential and plasma density fluctuations in the T-15MD tokamak using the Heavy Ion Beam Probe (HIBP) diagnostic. Four types of fluctuations are considered in the frequency range up to 500 kHz: Geodesic Acoustic Mode (GAM), Quasi-Coherent Mode (QCM), Tearing Mode (TM), and Alfvén eigenmode (AE). For each type of fluctuation, spatial measurement areas are defined for regimes with different values of average density \({{\bar {n}}_{e}}\) and toroidal magnetic field \({{B}_{T}}\) . Regimes with flat and peaked density profiles are considered. It is shown that high-Q fluctuations (GAM, AE, TM) can be measured in the peripheral region of the plasma \(\rho < 0.8\) up to density \({{\bar {n}}_{e}} \leqslant 7 \times {{10}^{{19}}}\;{{{\text{m}}}^{{ - 3}}}\) , while low-Q QCMs can be measured up to \({{\bar {n}}_{e}} \leqslant 5 \times {{10}^{{19}}}\;{{{\text{m}}}^{{ - 3}}}\) . In the plasma gradient region \(\rho = 0.5{-} 0.9\) the measurement of high-Q fluctuations is possible at a density of \({{\bar {n}}_{e}} \leqslant 5 \times {{10}^{{19}}}\;{{{\text{m}}}^{{ - 3}}}\) , and of the low-Q QCM at a density of \({{\bar {n}}_{e}} \leqslant 3 \times {{10}^{{19}}}\;{{{\text{m}}}^{{ - 3}}}\) .