Tesi etd-08112021-184113 |
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Tipo di tesi
Tesi di laurea magistrale
Autore
MANZINI, DAVIDE
URN
etd-08112021-184113
Titolo
Global and Local Dissipation in Collisionless Turbulent Plasmas
Dipartimento
FISICA
Corso di studi
FISICA
Relatori
relatore Sahraoui, Fouad
relatore Califano, Francesco
relatore Califano, Francesco
Parole chiave
- cascade
- dissipation
- kinetic
- les
- Navier-Stokes
- plasma
- simulations
- turbulence
Data inizio appello
15/09/2021
Consultabilità
Completa
Riassunto
The physics of turbulence in incompressible hydrodynamics follows a clear scheme: energy is injected at large scales, via non linear processes it cascades to smaller scales throughout the so called inertial range and it is eventually dissipated by molecular viscosity, which stems from inter-particles collisions.
In collisionless plasmas, even in the simplest limit of incompressible turbulence, the picture is much more complex. The presence of a mean magnetic field introduces characteristic scales of charged particles (first of all the electron and ion Larmor radius) that break the property of scale invariance. As a result, the range of scales is split into three different and interconnected ranges corresponding to three regimes in which the physics and therefore the energy transfer properties vary greatly. In addition, because of the absence of collisions, we face the difficulty of modeling dissipation and heating. On top of all the aforementioned complexity we have kinetic effects (Landau damping, cyclotron resonances, instabilities,...) at play in the plasma which impact the full dynamic and the cross scale energy transfer.
The central idea of this work is to study dissipation in kinetic collisionless plasma and in particular try to quantify the dissipation rate via the turbulent cascade rate and using an innovative spatial filtering method that allows us to quantify local energization.
In collisionless plasmas, even in the simplest limit of incompressible turbulence, the picture is much more complex. The presence of a mean magnetic field introduces characteristic scales of charged particles (first of all the electron and ion Larmor radius) that break the property of scale invariance. As a result, the range of scales is split into three different and interconnected ranges corresponding to three regimes in which the physics and therefore the energy transfer properties vary greatly. In addition, because of the absence of collisions, we face the difficulty of modeling dissipation and heating. On top of all the aforementioned complexity we have kinetic effects (Landau damping, cyclotron resonances, instabilities,...) at play in the plasma which impact the full dynamic and the cross scale energy transfer.
The central idea of this work is to study dissipation in kinetic collisionless plasma and in particular try to quantify the dissipation rate via the turbulent cascade rate and using an innovative spatial filtering method that allows us to quantify local energization.
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