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Titolo:
Dynamical cycles in charge and energy for iron ions accelerated in a hot plasma

Autore:

Indirizzi:: Univ Turku, Dept Phys, Space Res Lab, FIN-20014 Turku, Finland Univ TurkuTurku Finland FIN-20014 ace Res Lab, FIN-20014 Turku, Finland AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia AF Ioffe Phys Tech Inst St Petersburg Russia 194021 sburg 194021, Russia
Titolo Testata:: ASTROPHYSICAL JOURNAL
fascicolo: 2, volume: 556, anno: 2001,
parte:, 1
pagine: 919 - 927
SICI:: 0004-637X(20010801)556:2<919:DCICAE>2.0.ZU;2-I
Fonte:: ISI
Lingua:: ENG
Soggetto:: IMPULSIVE SOLAR-FLARES; STOCHASTIC FERMI ACCELERATION; PARTICLE-ACCELERATION; IMPACT IONIZATION; STATES; EQUILIBRIUM; SPECTRA; LOSSES; CORONA; EVENTS;
Keywords:: acceleration of particles; Sun : flares; Sun : particle emission;
Tipo documento:: Article
Natura:: Periodico
Settore Disciplinare:: Physical, Chemical & Earth Sciences
Citazioni:: 31
Recensione:
Indirizzi per estratti:: Indirizzo: Kocharov, L Univ Turku, Dept Phys, Space Res Lab, FIN-20014 Turku, FinlandUniv Turku Turku Finland FIN-20014 FIN-20014 Turku, Finland



Citazione:: L. Kocharov et al., "Dynamical cycles in charge and energy for iron ions accelerated in a hot plasma", ASTROPHYS J, 556(2), 2001, pp. 919-927

Abstract

We consider a unified model of Fe ion acceleration in the solar corona. The model comprises charge-changing processes, Coulomb energy losses, and both regular and stochastic acceleration. At a given acceleration scenario, the type of acceleration is found to have a minor effect on the mean charge states, but the shapes of the charge-state distributions produced by regularacceleration and by stochastic acceleration are different. During a continual acceleration at coronal temperatures, iron ions typically follow risingtrajectories on the charge-energy plane. These trajectories are situated below the mean equilibrium charge curve defined from the balance of ionization and recombination at fixed energy. During stopping, the iron ions cross the equilibrium charge curve and run through a series of charge states above the mean equilibrium charge at current energy, because the Coulomb deceleration rate significantly exceeds the rate of the ion recombination in a hot plasma. As a result, the variety of possible trajectories on the ion charge-energy plane turns out to be much wider than would be expected based on the equilibrium charge-state approximation. In particular, we find dynamical cycles in charge and energy, so that accelerated and highly stripped ionsmay reappear at low energies. We also find that the equilibrium charge curve cannot be reproduced without strong reduction in the total number of accelerated particles. This implies that the observed iron charge-state distributions essentially depend on the scenario of their acceleration and transport.

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Documento generato il 20/06/13 alle ore 13:39:43