Home Page of the Frascati Plasma Theory
Group
The
Frascati theoretical physics research program applied to the analysis
of
thermonuclear plasmas is characterized by various activities, ranging
from those with a direct impact on the presently urgent problems
regarding Next Step burning plasma experiments, such as
the ITER and IGNITOR projects, to those oriented to longer
term research plans.
Most of the theoretical investigations are pursued
within the larger frame of established international collaborations
with both National Laboratories and Universities. Among these, of primary importance are
the collaborations with the Princeton Plasma Physics Laboratory of Princeton University and
with the Department of Physics and Astronomy of the University of California at Irvine.
The research activity
on non-inductive current drive is one of practical importance to
present and future reactor-relevant experiments. Detailed analyses of
co- and counter-LHCD (Lower Hybrid Current Drive) have shown how to
build and sustain the required hollow current density profile for
reversed-shear operations in FTU. The same studies show the possibility
of obtaining the improved confinement properties, associated to
reversed-shear operations, in the IGNITOR plasmas. Non-inductive current-drive at
the Electron Cyclotron Resonant Frequency (ECRF) is crucial to control and/or suppress
Magneto-Hydro-Dynamic (MHD) plasma instabilities in reactor relevant regimes.
Analyses of RF (Radio Frequency) wave propagation and absorption
in toroidal plasmas makes it also possible to study optimal conditions for
plasma heating and for achieving improved confinement regimes. The investigation
of Ion Bernstein (IB) wave physics has provided the theoretical basis for explaining
some of the FTU improved performance regimes. Similarly, investigation of ECRF
heating is necessary to interpret the remarkable peaking of electron temperature
profile on FTU. Interpretative and predictive transport modeling are the natural framework
for comparisons with experimental results.
Theoretical studies of
the dynamic properties of fusion products in ignited plasmas and of MeV
energetic ions produced by RF/NBI (Neutral Beam Injection) are carried
out along two major research lines. The first, of direct impact on
ITER, consists of numerical simulations of the energetic particle
interaction with Alfvén waves via a hybrid MHD-gyrokinetic code (HMGC).
These numerical studies, based on Particle In Cell (PIC) simulation codes, have demonstrated that the thresholds
for linear Energetic Particle Mode (EPM) excitation and nonlinear behaviors (transport) of energetic ions are essentially the same, emphasizing the crucial role played by
the resonant collective mode excitation threshold in a thermonuclear plasma. The second research line, oriented to the
analysis of the fundamental processes associated to the propagation of
Alfvén waves in ignited plasmas, is pursued within a
collaboration with the University of California at Irvine and has
recently addressed the issue of the relevance of low frequency
Alfvén waves to transport of both thermal and energetic
components of a reactor plasma.
Most of the burning plasma physics analyses are made possible only via developments of very advanced,
massively parallelized numerical codes (such as the HMGC, developed in Frascati) and of adequate representation techniques of simulation results.
These activities are characterized by great complexity, as it is commonly the case with high performance computing. However, they are extremely
attractive for their potential impact and use in neighboring areas of research. Accelerator physics is one of these, but potential applications can be also envisaged in the apparently remote field of car-traffic simulations.