Sus - Anna | University of Genova (original) (raw)
Papers by Sus - Anna
Elsevier eBooks, 1991
The temperature profiles of tokamak plasmas are obtained from a solution of the generalized Ohm&#... more The temperature profiles of tokamak plasmas are obtained from a solution of the generalized Ohm's law, taking into account neoclassical resistivity, bootstrap currents, and nonstationary effects. These profiles have been coupled to a MHD equilibrium code and to a zero-dimensional transport code to simulate time dependent tokamak discharges. In this report, some examples are given of the effect on plasma equilibrium, flux consumption, and fusion plasma performances of strong temperature peaking due to nonstationary conditions. The present approach allows estimates of the current diffusion times inside the plasma volume, when nonstationary effects are taken into account. These estimates have been shown to account both for the temperature profiles and for the stabilization times of monsters and giant sawteeth at JET and have been assumed in the time dependent simulations given in this report.
Journal of Plasma Physics, Jun 1, 2022
Independent assessment of the feasibility of controlled nuclear fusion in the proposed SPARC toka... more Independent assessment of the feasibility of controlled nuclear fusion in the proposed SPARC tokamak (Creely et al., J. Plasma Phys., vol. 86, 2020, 865860502; Rodriguez-Fernandez et al., J. Plasma Phys., vol. 86, 2020, 865860503) is difficult because of the uncertainties concerning energy transport in the plasma. We discuss a SPARC scenario – where a burning plasma is obtained – with the help of a well-known general constraint on transport in weakly collisional, axisymmetric, toroidal, low- beta\betabeta turbulent plasma (Rogister et al., Phys. Fluids B, vol. 4, 1992, p. 804). This constraint is useful in reducing uncertainties on auxiliary heating as the fusion gain begins to be large. No particular ad hoc model for transport coefficients is invoked. The crucial roles of both suitable tuning of ion cyclotron radiofrequency power and high-temperature pedestal are highlighted.
European Physical Journal B, Feb 1, 2020
Abstract In monodimensional systems where a nonlinear Fokker-Planck equation [G.A. Casas et al., ... more Abstract In monodimensional systems where a nonlinear Fokker-Planck equation [G.A. Casas et al., Phys. Rev. E 86 , 061136 (2012)] describes relaxation to a distribution function which behaves like a power law in the tail, we show that perturbations of the relaxed distribution behave as avalanches in the sense of Self Organized Criticality [J. Nagler et al., Phys. Rev. E 60 , 2706 (1999)]. We determine the power laws followed by both size and return time of these avalanches whenever the relaxed distribution is resilient against perturbation of arbitrary amplitude in the tail. We apply our results to a class of problems in econophysics [J.R. Sanchez et al., Europhys. J. 143 , 241 (2007)] where the relaxed distribution of wealth is approximately described by Pareto’s principle [A. Di Vita, Europhys. J. 92 , 255 (2019)]. If the destruction of wealth associated with an avalanche is identified with a war, then we retrieve Richardson’s model of arms race [L.F. Richardson, Nature 136 , 1025 (1935)], prove that the largest avalanches follow Richardson’s scaling law of warfare [L.F. Richardson, J. Am. Stat. Assoc. 43 , 244 (1948)] and show that the probability of war outbreak per unit time follows a Poisson law [L.F. Richardson, Nature 155 , 610 (1945)], in agreement with the findings of [L. Cederman, Am. Polit. Sci. Rev. 97 , 135 (2003), A. Clauset, Sci. Adv. 4 (2018), G. Martelloni et al. arXiv:1812.08071 (2018)]. Graphical abstract
Nuclear Fusion, Sep 8, 2010
... plasma Andrea Di Vita DICAT, Universita' di Genova-1, via Montallegro-16145 Genova, ... more ... plasma Andrea Di Vita DICAT, Universita' di Genova-1, via Montallegro-16145 Genova, Italy E-mail: anna andrea.divita@tin.it Received 10 May 2010, accepted for publication 10 August 2010 Published 8 September 2010 Online at stacks.iop.org/NF/50/115001 ...
Plasma Sources Science and Technology, Jan 25, 2017
Lecture Notes in Physics, 2022
Lecture Notes in Physics, 2022
Lecture Notes in Physics, 2022
Lecture Notes in Physics, 2022
Lecture Notes in Physics, 2022
Lecture Notes in Physics, 2022
Elsevier eBooks, 1991
The temperature profiles of tokamak plasmas are obtained from a solution of the generalized Ohm&#... more The temperature profiles of tokamak plasmas are obtained from a solution of the generalized Ohm's law, taking into account neoclassical resistivity, bootstrap currents, and nonstationary effects. These profiles have been coupled to a MHD equilibrium code and to a zero-dimensional transport code to simulate time dependent tokamak discharges. In this report, some examples are given of the effect on plasma equilibrium, flux consumption, and fusion plasma performances of strong temperature peaking due to nonstationary conditions. The present approach allows estimates of the current diffusion times inside the plasma volume, when nonstationary effects are taken into account. These estimates have been shown to account both for the temperature profiles and for the stabilization times of monsters and giant sawteeth at JET and have been assumed in the time dependent simulations given in this report.
Journal of Plasma Physics, Jun 1, 2022
Independent assessment of the feasibility of controlled nuclear fusion in the proposed SPARC toka... more Independent assessment of the feasibility of controlled nuclear fusion in the proposed SPARC tokamak (Creely et al., J. Plasma Phys., vol. 86, 2020, 865860502; Rodriguez-Fernandez et al., J. Plasma Phys., vol. 86, 2020, 865860503) is difficult because of the uncertainties concerning energy transport in the plasma. We discuss a SPARC scenario – where a burning plasma is obtained – with the help of a well-known general constraint on transport in weakly collisional, axisymmetric, toroidal, low- beta\betabeta turbulent plasma (Rogister et al., Phys. Fluids B, vol. 4, 1992, p. 804). This constraint is useful in reducing uncertainties on auxiliary heating as the fusion gain begins to be large. No particular ad hoc model for transport coefficients is invoked. The crucial roles of both suitable tuning of ion cyclotron radiofrequency power and high-temperature pedestal are highlighted.
European Physical Journal B, Feb 1, 2020
Abstract In monodimensional systems where a nonlinear Fokker-Planck equation [G.A. Casas et al., ... more Abstract In monodimensional systems where a nonlinear Fokker-Planck equation [G.A. Casas et al., Phys. Rev. E 86 , 061136 (2012)] describes relaxation to a distribution function which behaves like a power law in the tail, we show that perturbations of the relaxed distribution behave as avalanches in the sense of Self Organized Criticality [J. Nagler et al., Phys. Rev. E 60 , 2706 (1999)]. We determine the power laws followed by both size and return time of these avalanches whenever the relaxed distribution is resilient against perturbation of arbitrary amplitude in the tail. We apply our results to a class of problems in econophysics [J.R. Sanchez et al., Europhys. J. 143 , 241 (2007)] where the relaxed distribution of wealth is approximately described by Pareto’s principle [A. Di Vita, Europhys. J. 92 , 255 (2019)]. If the destruction of wealth associated with an avalanche is identified with a war, then we retrieve Richardson’s model of arms race [L.F. Richardson, Nature 136 , 1025 (1935)], prove that the largest avalanches follow Richardson’s scaling law of warfare [L.F. Richardson, J. Am. Stat. Assoc. 43 , 244 (1948)] and show that the probability of war outbreak per unit time follows a Poisson law [L.F. Richardson, Nature 155 , 610 (1945)], in agreement with the findings of [L. Cederman, Am. Polit. Sci. Rev. 97 , 135 (2003), A. Clauset, Sci. Adv. 4 (2018), G. Martelloni et al. arXiv:1812.08071 (2018)]. Graphical abstract
Nuclear Fusion, Sep 8, 2010
... plasma Andrea Di Vita DICAT, Universita' di Genova-1, via Montallegro-16145 Genova, ... more ... plasma Andrea Di Vita DICAT, Universita' di Genova-1, via Montallegro-16145 Genova, Italy E-mail: anna andrea.divita@tin.it Received 10 May 2010, accepted for publication 10 August 2010 Published 8 September 2010 Online at stacks.iop.org/NF/50/115001 ...
Plasma Sources Science and Technology, Jan 25, 2017
Lecture Notes in Physics, 2022
Lecture Notes in Physics, 2022
Lecture Notes in Physics, 2022
Lecture Notes in Physics, 2022
Lecture Notes in Physics, 2022
Lecture Notes in Physics, 2022