The role of alpha particles in the emission of plasma waves inside solar ejecta

Dasso, S.; Gratton, F. T.; Farrugia, C. J.

doi:10.1590/s0103-97332002000300026

Cited by 2 publications

(3 citation statements)

References 6 publications

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“…The possibility that RH‐EICWs may be excited in ICMEs, as a consequence of A p < 0 was first considered by Farrugia et al [1998a]. Preliminary examinations of the influence of the thermal properties of protons and α particles, on the EICW instability for ICMEs conditions was given by Dasso et al [1999] and Dasso et al [2002]. Explorative analysis of effects of hot and anisotropic electrons have been developed in Gratton et al [1998] and Dasso et al [2000].…”

Section: Introductionmentioning

confidence: 99%

A parametric study of the influence of ion and electron properties on the excitation of electromagnetic ion cyclotron waves in coronal mass ejections

2003

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[1] Interplanetary coronal mass ejections (ICMEs) often possess a negative proton thermal anisotropy, A p = T ?,p /T k,p À 1 < 0 (T k , T ? : parallel and perpendicular temperatures, respectively) so that right-hand polarized electromagnetic ion cyclotron waves (EICWs) may be amplified by a kinetic instability [Farrugia et al., 1998a]. However, in view of the low proton beta of ICMEs, several physical parameters, besides A p , need to be in the right range to excite this instability with significant growth rates. In this paper we present a parametric study of EICWs aimed at identifying those parameters which are most influential in fostering the emission of these waves in ICME scenarios. We analyze here the influence of: (1) thermal and suprathermal protons, (2) thermal alpha particles (as), and (3) thermal electrons. We solve the dispersion relation of EICWs including protons, as and electrons, all modeled with bi-Maxwellian distribution functions, and a minority population of suprathermal protons using a kappa function for the velocity component along the field. For physical regimes of ICMEs we find that the instability depends critically on the values of the following parameters: proton beta, proton thermal anisotropy, relative abundance of the suprathermal protons, a-to-proton relative abundance, a-to-proton temperature ratio, a particle thermal anisotropy, electron-toproton temperature ratio, and thermal anisotropy of electrons. The effect of these parameters on the instability is either direct (when they increase the number of resonant particles) or indirect (when they decrease the phase speed of the wave so that more particles can resonate). Data surveys on EICWs should take into account the whole set of parameters indicated here, since the expected level of wave excitation results from their combined action. The study may be useful in understanding the considerable level of magnetic fluctuations observed in interplanetary CMEs by the Wind spacecraft. Citation: Dasso, S., F. T. Gratton, and C. J. Farrugia, A parametric study of the influence of ion and electron properties on the excitation of electromagnetic ion cyclotron waves in coronal mass ejections,

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Section: Introductionmentioning

confidence: 99%

A parametric study of the influence of ion and electron properties on the excitation of electromagnetic ion cyclotron waves in coronal mass ejections

2003

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“…As a result, the dispersion equation for field-aligned electromagnetic cyclotron waves (see e.g. Abramovitz and Stegun, 1972;Bespalov and Trakhtengerts, 1986;Bittencourt, 1986;Chan et al, 1994;Chen and Hasegawa, 1991;Cornwall, 1965;Cuperman, 1981;Dasso et al, 2002;Dettrick et al, 2003) in magnetized plasmas, confined in the straight magnetic field, has the well-known form (see, e.g. Kennel and Petschek, 1966;Xue et al, 1996) similar to Eqs.…”

Section: Magnetized Plasma In the Straight Magnetic Field (Bimaxwellimentioning

confidence: 99%

“…Grishanov (nikolay@lncc.br) netic theory of electromagnetic cyclotron waves/instabilities in the straight magnetic field plasma is well developed (see, e.g. the publications by Sagdeev and Shafranov, 1961;Cornwall, 1965;Kennel and Petschek, 1966;Horng, 1977;Cuperman, 1981;Gomberoff and Neira, 1983;Kozyra et al, 1984;Bespalov and Trakhtengerts, 1986;Bittencourt, 1986;Gary, 1993;Xue et al, 1996;Dasso et al, 2002;Khazanov et al, 2003;and bibliography therein). However, the models of uniform plasmas confined in the straight magnetic field are suitable to study the wave processes in the solar wind and quite rough for the planetary magnetospheres, which are three-dimensional in the general case.…”

Section: Introductionmentioning

confidence: 99%

Dispersion equations for field-aligned cyclotron waves in axisymmetric magnetospheric plasmas

et al. 2006

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Abstract. In this paper, we derive the dispersion equations for field-aligned cyclotron waves in two-dimensional (2-D) magnetospheric plasmas with anisotropic temperature. Two magnetic field configurations are considered with dipole and circular magnetic field lines. The main contribution of the trapped particles to the transverse dielectric permittivity is estimated by solving the linearized Vlasov equation for their perturbed distribution functions, accounting for the cyclotron and bounce resonances, neglecting the drift effects, and assuming the weak connection of the left-hand and right-hand polarized waves. Both the bi-Maxwellian and bi-Lorentzian distribution functions are considered to model the ring current ions and electrons in the dipole magnetosphere. A numerical code has been developed to analyze the dispersion characteristics of electromagnetic ion-cyclotron waves in an electron-proton magnetospheric plasma with circular magnetic field lines, assuming that the steady-state distribution function of the energetic protons is bi-Maxwellian. As in the uniform magnetic field case, the growth rate of the proton-cyclotron instability (PCI) in the 2-D magnetospheric plasmas is defined by the contribution of the energetic ions/protons to the imaginary part of the transverse permittivity elements. We demonstrate that the PCI growth rate in the 2-D axisymmetric plasmasphere can be significantly smaller than that for the straight magnetic field case with the same macroscopic bulk parameters.

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The role of alpha particles in the emission of plasma waves inside solar ejecta

Cited by 2 publications

References 6 publications

A parametric study of the influence of ion and electron properties on the excitation of electromagnetic ion cyclotron waves in coronal mass ejections

A parametric study of the influence of ion and electron properties on the excitation of electromagnetic ion cyclotron waves in coronal mass ejections

Dispersion equations for field-aligned cyclotron waves in axisymmetric magnetospheric plasmas

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