Seminari di Fisica Matematica
Home |
Archivio |
| 2018-2019 |
| 2017-2018 |
| 2016-2017 |
| 2015-2016 |
| 2014-2015 |
| 2013-2014 |
| 2012-2013 |
| 2011-2012 |
| 2010-2011 |
| 2009-2010 |
| 2008-2009 |
| 2007-2008 |
| 2006-2007 |
| 2005-2006 |
| 2004-2005 |
| 2003-2004 |
| 2002-2003 |
| 2001-2002 |
| Seminari A.A. 2012-2013 |
||||
|
|
||||
Relatore |
Titolo |
Data |
||
|---|---|---|---|---|
|
Omar Maj
Max-Planck Inst. für Plasmaphys. Garching |
02 Luglio 2013 (ore 14:00) |
|||
|
Marco Brambilla
Max-Planck Inst. für Plasmaphys. Garching |
11 Giugno 2013 |
|||
|
Abstract ritorna |
In the first part of this talk we point out that the linear electrodynamics
of hot plasmas must be formulated in a different way compared to ordinary dielectrics
or conductors. The difference is due to the fact that in a hot plasma collisions
are so rare that the mean free path of charged particles are much longer than the typical
wavelengths of all modes of plasma electromagnetic oscillations.
As a consequence, the plasma is dispersive both in time and space.
In an infinite homogeneos plasma space dispersion is reflected in the fact
that the conductivity tensor depends on the wavevector of each plane wave considered.
Since plane waves, on the other hand, are not eigenmodes of real, non-uniform plasmas,
space dispersion makes it very difficult to solve the linearized Vlasov equation to
obtain the constitutive relation, i.e. the linear relation between high frequency
current and field in the plasma. In magnetically confined plasmas the particle orbits
are multi-periodic. This has suggested (Kaufmann 1972) the use of action-angle variables
to solve the problem. This approach is fascinatingly simple and elegant, but the results,
if taken literally, lead to predictions which contraddict expectation and experimental evidence.
Investigating the reason of these paradoxes is very interesting, since it is a
first step to understand how irreversibility arises from a reversible model,
and to the construction of a consistent 'closed' theory of linear wave propagation
in plasmas. In the second part of the talk we sketch the solution of the linearized
Vlasov equation with the spectral method.
The integral, non local constitutive relation obtained in this way is
very complicated, but physically transparent,
and is, therefore, a good starting point for approximations based on clearly
formulated assumptions, which lead to wave equations valid for concrete problems,
and which can be numerically solved with a reasonable effort.
To confirm this, we will finally show a few pictures of wave
propagation in tokamaks in the Ion Cyclotron range
of frequencies, obtained with the full-wave solver TORIC. |
|||
|
Mustapha Mourragui
Université de Rouen |
16 Maggio 2013 (giovedì) |
|||
|
Mustapha Mourragui
Université de Rouen |
15 Maggio 2013 (mercoledì) |
|||
|
Bruno Coppi
MIT |
14 Maggio 2013 (ore 15:00) |
|||
|
Francesco Califano
Università di Pisa |
14 Maggio 2013 (ore 14:00) |
|||
|
Alain Messager
CPT - CNRS Marseille |
Phase transitions in the long range XXZ model |
07 Maggio 2013 (ore 15:30) |
||
|
Carlo Marchioro
Università di Roma "La Sapienza" |
07 Maggio 2013 |
|||
|
Milos Zahradnik
Charles University Prague |
30 Aprile 2013 (ore 15:00) |
|||
|
Daniela Grasso
CNR e Politecnico di Torino |
30 Aprile 2013 (ore 14:00) |
|||
|
Yuri Kondratev
Universität Bielefeld |
23 Aprile 2013 |
|||
|
Israel Michael Sigal
Toronto University |
12 Aprile 2013 (venerdì) |
|||
|
Errico Presutti
Università di Roma "Tor Vergata" |
09 Aprile 2013 |
|||
|
Giovanni Gallavotti
INFN Roma1 e Accademia dei Lincei |
05 Marzo 2013 |
|||
|
Alessandro Pizzo
UC Davis |
23 Ottobre 2012 (ore 16:00) |
|||
|
Zhituo Wang
Paris XI - Orsay |
26 Settembre 2012 (mercoledì) |
|||
|
Joel Lebowitz
Rutgers University |
Three easy (to state) open problems (that have worried me for many years) |
24 Settembre 2012 (lunedì 16:00 aula F) |
||
|
Manuel de Llano
UNAM |
21 Settembre 2012 (venerdì) |
|||