Analysis of the Chaotic Behavior of the Lower Hybrid Wave Propagation in Magnetised Plasma by Hamiltonian Theory
The Hamiltonian character of the ray tracing equations describing the propagation of the Lower Hybrid Wave (LHW) in a magnetic confined plasma device (tokamak) is investigated in order to study the evolution of the parallel wave number along the propagation path. The chaotic diffusion of the “time-a...
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doaj-908bc74c4264471f88310a9ae6459b402020-11-24T22:55:15ZengMDPI AGEntropy1099-43002016-05-0118517510.3390/e18050175e18050175Analysis of the Chaotic Behavior of the Lower Hybrid Wave Propagation in Magnetised Plasma by Hamiltonian TheoryAndrea Casolari0Alessandro Cardinali1Dipartimento di Fisica Enrico Fermi, Università di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa, ItalyAssociazione Euratom-ENEA sulla Fusione, Via E. Fermi 45, C.P. 65, I-00044 Frascati, ItalyThe Hamiltonian character of the ray tracing equations describing the propagation of the Lower Hybrid Wave (LHW) in a magnetic confined plasma device (tokamak) is investigated in order to study the evolution of the parallel wave number along the propagation path. The chaotic diffusion of the “time-averaged” parallel wave number at higher values (with respect to that launched by the antenna at the plasma edge) has been evaluated, in order to find an explanation of the filling of the spectral gap (Fisch, 1987) by “Hamiltonian chaos” in the Lower Hybrid Current Drive (LHCD) experiments (Fisch, 1978). The present work shows that the increase of the parallel wave number \(n_{\parallel}\) due to toroidal effects, in the case of the typical plasma parameters of the Frascati Tokamak Upgrade (FTU) experiment, is insufficient to explain the filling of the spectral gap, and the consequent current drive and another mechanism must come into play to justify the wave absorption by Landau damping. Analytical calculations have been supplemented by a numerical algorithm based on the symplectic integration of the ray equations implemented in a ray tracing code, in order to preserve exactly the symplectic character of a Hamiltonian flow.http://www.mdpi.com/1099-4300/18/5/175tokamak plasmaslower hybridHamiltonian theory52.55.-s52.50.-b52.35.-g52.25.Gj |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Andrea Casolari Alessandro Cardinali |
spellingShingle |
Andrea Casolari Alessandro Cardinali Analysis of the Chaotic Behavior of the Lower Hybrid Wave Propagation in Magnetised Plasma by Hamiltonian Theory Entropy tokamak plasmas lower hybrid Hamiltonian theory 52.55.-s 52.50.-b 52.35.-g 52.25.Gj |
author_facet |
Andrea Casolari Alessandro Cardinali |
author_sort |
Andrea Casolari |
title |
Analysis of the Chaotic Behavior of the Lower Hybrid Wave Propagation in Magnetised Plasma by Hamiltonian Theory |
title_short |
Analysis of the Chaotic Behavior of the Lower Hybrid Wave Propagation in Magnetised Plasma by Hamiltonian Theory |
title_full |
Analysis of the Chaotic Behavior of the Lower Hybrid Wave Propagation in Magnetised Plasma by Hamiltonian Theory |
title_fullStr |
Analysis of the Chaotic Behavior of the Lower Hybrid Wave Propagation in Magnetised Plasma by Hamiltonian Theory |
title_full_unstemmed |
Analysis of the Chaotic Behavior of the Lower Hybrid Wave Propagation in Magnetised Plasma by Hamiltonian Theory |
title_sort |
analysis of the chaotic behavior of the lower hybrid wave propagation in magnetised plasma by hamiltonian theory |
publisher |
MDPI AG |
series |
Entropy |
issn |
1099-4300 |
publishDate |
2016-05-01 |
description |
The Hamiltonian character of the ray tracing equations describing the propagation of the Lower Hybrid Wave (LHW) in a magnetic confined plasma device (tokamak) is investigated in order to study the evolution of the parallel wave number along the propagation path. The chaotic diffusion of the “time-averaged” parallel wave number at higher values (with respect to that launched by the antenna at the plasma edge) has been evaluated, in order to find an explanation of the filling of the spectral gap (Fisch, 1987) by “Hamiltonian chaos” in the Lower Hybrid Current Drive (LHCD) experiments (Fisch, 1978). The present work shows that the increase of the parallel wave number \(n_{\parallel}\) due to toroidal effects, in the case of the typical plasma parameters of the Frascati Tokamak Upgrade (FTU) experiment, is insufficient to explain the filling of the spectral gap, and the consequent current drive and another mechanism must come into play to justify the wave absorption by Landau damping. Analytical calculations have been supplemented by a numerical algorithm based on the symplectic integration of the ray equations implemented in a ray tracing code, in order to preserve exactly the symplectic character of a Hamiltonian flow. |
topic |
tokamak plasmas lower hybrid Hamiltonian theory 52.55.-s 52.50.-b 52.35.-g 52.25.Gj |
url |
http://www.mdpi.com/1099-4300/18/5/175 |
work_keys_str_mv |
AT andreacasolari analysisofthechaoticbehaviorofthelowerhybridwavepropagationinmagnetisedplasmabyhamiltoniantheory AT alessandrocardinali analysisofthechaoticbehaviorofthelowerhybridwavepropagationinmagnetisedplasmabyhamiltoniantheory |
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1725657252761698304 |