Estimate of the Conversion of the Plasma Current Magnetic Energy to the Kinetic Energy of Runaway Electrons in a Tokamak within a Zero-Dimensional Model
https://doi.org/10.1134/S2304487X20060097
Abstract
The conversion of the poloidal magnetic field energy created by the toroidal plasma current into the kinetic energy of runaway electrons during the termination phase of the plasma discharge disruption in a tokamak is analyzed within the zero-dimensional model of infinitely thin ring conductors. The evolution equations for the plasma current and the induced current in the wall of the vacuum chamber, which are based on the Faraday’s law of electromagnetic induction, are solved analytically. The time dependences of the mentioned currents are obtained under the condition of an exponential decay of the runaway electron current, which makes it possible to determine the efficiency of the specified conversion. When additional conditions are imposed on the parameters of the system, the expressions for the total plasma current and the current in the wall of the tokamak vacuum chamber reproduce similar relations obtained in earlier works. For the extreme cases of an ideal wall (when its resistance is infinitely small) and a wall with infinite resistance, simplified relations for the total plasma current are given, and estimates for the fraction of the magnetic field energy converted into the kinetic energy of runaway electrons are also obtained which are necessary to analyze the thermal load on the elements of the first tokamak walls in the case of disruptions of plasma discharges.
About the Author
V. Yu. Savin
National Research Nuclear University MEPhI (Moscow Engineering Physics Institute)
Russian Federation
Russian Federation
115409
Moscow
References
1. Riemann J., Smith H. M., Helander P. Energetics of runaway electrons during tokamak disruptions // Phys. Plasmas. 2012. V. 19. № 1. P. 012507. doi: 10.1063/1.3671974
2. Martín-Solís J. R., Loarte A., Hollmann E. M., Esposito B., Riccardo V. Inter-machine comparison of the termination phase and energy conversion in tokamak disruptions with runaway current plateau formation and implications for ITER // Nucl. Fusion. 2014. V. 54. № 8. P. 083027. doi: 10.1088/0029-5515/54/8/083027
3. Dai A. J. et al. Conversion of magnetic energy to runaway kinetic energy during the termination of runaway current on the J-TEXT tokamak // Plasma Phys. Control. Fusion. 2018. V. 60. № 5. P. 055003. doi: 10.1088/1361-6587/aab16d
4. Pustovitov V. D. Extension of Shafranov’s Equilibrium Theory to the Description of Current Quenches Affected by Resistive Wall Dissipation in Tokamaks // Plasma Physics Reports. 2019. V. 45. № 12. P. 1114–1127. doi: 10.1134/S1063780X19120079
5. Breizman B. N., Aleynikov P., Hollmann E. M., Lehnen M. Physics of runaway electrons in tokamaks // Nucl. Fusion. 2019. V. 59. № 8. P. 083001. doi: 10.1088/1741-4326/ab1822
Review
For citations:
Savin V.Yu. Estimate of the Conversion of the Plasma Current Magnetic Energy to the Kinetic Energy of Runaway Electrons in a Tokamak within a Zero-Dimensional Model. Vestnik natsional'nogo issledovatel'skogo yadernogo universiteta "MIFI". 2020;9(6):485-488. (In Russ.) https://doi.org/10.1134/S2304487X20060097
Views:
121
Email this article 