Abstract:Geodesic acoustic mode (GAM) in collisionless toroidal plasmas with a constant electrostatic potential around a magnetic surface is investigated based on the linear gyrokinetic theory in context of nonextensive statistics mechanics. The damping rate of GAM is shown to be dependent on the nonextensive parameters of ions, and in the extensive limit, the result in Maxwellian distribution plasma is recovered. The damping rate is found to be enhanced as the nonextensive parameter of ion decreases.
“…1) increases with the decrease of the nonextensive parameter q as shown in Fig. 2, which are in line with the results obtained by Qiu et al [30], in which only one species of ion is considered. The terms containing τ j in the factors d 3 and d 4 can be omitted when the finite electron temperature effect is out of consideration.…”
Section: Discussionsupporting
confidence: 92%
“…Theoretical results on ion acoustic waves [27] and dispersive Alfvén waves [28] in nonextensive plasmas have been reported, as well as experimental observation data which fits well with the model based on Tasllis statistics [29]. In particular, the collisionless damping of the GAM in two-component electron-ion plasmas with nonextensively distributed ions has been studied from the linear gyrokinetic theory [30], in which the effect of finite electron temperature is neglected.…”
The dispersion relation of geodesic acoustic mode is investigated in a multi-ion toroidal plasma on the basis of linear gyrokinetic equations where ions are assumed to take a nonextensive distribution. It is found that the frequency of GAM becomes larger with the decrease of q. Consequently, GAM will damp more rapidly. The effective charge corresponding to the maximum damping rate is found to move towards unity as q decreases. As indicates that in a plasma with superthermal bulk ions, the influence of the impurity ion on the damping rate is weakened.
“…1) increases with the decrease of the nonextensive parameter q as shown in Fig. 2, which are in line with the results obtained by Qiu et al [30], in which only one species of ion is considered. The terms containing τ j in the factors d 3 and d 4 can be omitted when the finite electron temperature effect is out of consideration.…”
Section: Discussionsupporting
confidence: 92%
“…Theoretical results on ion acoustic waves [27] and dispersive Alfvén waves [28] in nonextensive plasmas have been reported, as well as experimental observation data which fits well with the model based on Tasllis statistics [29]. In particular, the collisionless damping of the GAM in two-component electron-ion plasmas with nonextensively distributed ions has been studied from the linear gyrokinetic theory [30], in which the effect of finite electron temperature is neglected.…”
The dispersion relation of geodesic acoustic mode is investigated in a multi-ion toroidal plasma on the basis of linear gyrokinetic equations where ions are assumed to take a nonextensive distribution. It is found that the frequency of GAM becomes larger with the decrease of q. Consequently, GAM will damp more rapidly. The effective charge corresponding to the maximum damping rate is found to move towards unity as q decreases. As indicates that in a plasma with superthermal bulk ions, the influence of the impurity ion on the damping rate is weakened.
“…Here we show the measurement of ion nonextensive parameter of plasma based on the theory of nonextensive geodesic acoustic modes. We assume that the plasma to be measured can be described by nonextensive statistical mechanics, and on this basis, establish the nonextensive geodesic acoustic mode theory 6 . Using this theory, we have measured the ion nonextensive parameter of 1.565 which cannot be measured even by a nonextensive single electric probe 1 .…”
Section: Introductionmentioning
confidence: 99%
“…In addition, the measurement of ion nonextensive parameter is closely related to the study of various plasma waves, instabilities, turbulence and abnormal transport. A defined and quantitative test of nonextensive geodesic acoustic mode theory 6 will be relevant for such developments. Figure 1 Schematic of ion nonextensive parameter diagnosis method based on nonextensive geodesic acoustic mode theory.…”
Section: Introductionmentioning
confidence: 99%
“…The ion nonextensive parameter diagnosis method based on nonextensive geodesic acoustic mode theory is a method that adopts the nonextensive geodesic acoustic mode theory 6 as a foundation and combines the measurement of geodesic acoustic mode frequency and plasma electron temperature to give ion nonextensive parameter (Fig. 1 ).…”
The consideration of nonextensivity effects is crucial to the accurate diagnosis of plasma parameters; common plasma nonextensive parameters include electron nonextensive parameter and ion nonextensive parameter, and the former can be measured, while the ion nonextensive parameter cannot be measured yet. Here we show the measurement of ion nonextensive parameter of plasma based on the theory of nonextensive geodesic acoustic modes. We assume that the plasma to be measured can be described by nonextensive statistical mechanics, and on this basis, the nonextensive geodesic acoustic mode theory is established. Utilizing this theory, we have measured the ion nonextensive parameter $${{q}_{{{F}_{\mathrm {i}}}}}= 1.565$$
q
F
i
=
1.565
which cannot be diagnosed even by a nonextensive single electric probe. Our research points out that the proposed measurement method of ion nonextensive parameter may play a role in plasma diagnosis and will help us to grasp the nonextensivity of plasma more precisely. We hope the proposed method of ion nonextensive parameter diagnosis based on the nonextensive geodesic acoustic mode theory can be the starting point of more complex ion nonextensive parameter diagnosis methods. In addition, the measurement of ion nonextensive parameter is closely related to the study of various plasma waves, instabilities, turbulence and abnormal transport, and a defined and quantitative test of nonextensive geodesic acoustic mode theory will bound up deeply with such developments.
It is a great physical challenge to achieve controlled nuclear fusion in magnetic confinement tokamak and solve energy shortage problem for decades. In tokamak plasma, large-scale plasma instability called disruption will halt power production of reactor and damage key components. Prediction and prevention of plasma disruption is extremely urgent and important. However, there is no analytical theory can elucidate plasma disruption physical mechanism yet. Here we show an analytical theory of tokamak plasma disruption based on nonextensive geodesic acoustic mode theory, which can give the physical mechanism of disruption. The proposed theory has not only been confirmed by experimental data of disruption on T-10 device, but also can explain many related phenomena around plasma disruption, filling the gap in physical mechanism of tokamak plasma disruption.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
