Resonant acceleration and heating of solar wind ions by dispersive ion cyclotron waves

Hu, Yingying; Habbal, Shadia Rifai

doi:10.1029/1999ja900193

Cited by 84 publications

(68 citation statements)

References 37 publications

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“…This, together with the considerably higher O vi kinetic temperatures found in the examined regions, confirms the possibility of energy deposition and plasma heating and acceleration through the absorption of Alfvén waves at ion cyclotron frequency (e.g., Li et al 1997Li et al , 1999Tu & Marsch 1997;Cranmer et al, 1999aCranmer et al, , 1999bHu & Habbal, 1999), both along the boundaries of the streamer structure and immediately outside it.…”

Section: Derivation Of the Physical Parameterssupporting

confidence: 51%

Physical parameters along the boundaries of a mid-latitude streamer and in its adjacent regions

Susino¹,

Ventura

Spadaro

et al. 2008

A&A

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Context. Coronal streamers appear to be strictly associated with the generation of the slow solar wind, even if a firm identification of the sources of the particle flux within these structures is still an unresolved issue. Aims. The purpose of this work is to contribute to a better knowledge of the physical characteristics of streamers and of their surroundings in a wide range of heliocentric distances and at both high radial and latitudinal resolutions. Methods. The analysis is based on spectral observations of a narrow, mid-latitude streamer performed with UVCS/SOHO during one week in May 2004: H i Lyα and O vi resonance doublet line intensities and profiles were obtained at different heliocentric distances and latitudes. In addition, white-light polarized brightness images were taken in the same days of observation, through the LASCO/SOHO C2 coronagraph.Results. The radial variations in electron density and temperature, H i and O vi kinetic temperatures, and outflow velocities were derived from the observed line intensities, profiles, and O vi line intensity ratios between 1.6 and 5.0 R , in two regions, 2-3 arcmin wide, located along the boundaries and in a narrow strip (5-10 arcmin) outside the streamer structure. Significantly high kinetic temperatures and outflow velocities were found in the out-of-streamer region above 3.0 R for the O vi ions and, for the first time, H i atoms, compared to those obtained along the streamer boundaries. Moreover, the O vi kinetic temperatures and velocities turn out much higher than the H i ones at any heliocentric distance in all the observed regions. A higher anisotropy is also noticed for the O vi kinetic temperature in the region flanking the streamer. Conclusions. The slow coronal wind is found to flow with significantly different speeds and kinetic temperatures along the boundaries of the streamer and in the out-of-streamer regions at all heights, above 3.0-3.5 R . This fact, consistent with previous studies, indicates that two components of slow wind probably form in the observed regions: one originates just above the streamer cusp and flows with velocities a little higher than 100 km s −1 , while the other flows along the open magnetic field lines flanking the streamer with velocities slightly lower than the slow wind asymptotic heliospheric value of ∼400 km s −1 , around 5.0 R .

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Section: Derivation Of the Physical Parameterssupporting

confidence: 51%

Physical parameters along the boundaries of a mid-latitude streamer and in its adjacent regions

Susino¹,

Ventura

Spadaro

et al. 2008

A&A

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“…The corresponding magnetic power density near 160 Hz at 2.5 R is about 1000 nT 2 Hz −1 . We notice that the power density presented by Hu et al (1999) at the same frequency and the same heliocentric distance is about 2000 nT 2 Hz −1 (see their Fig. 3).…”

Section: Numerical Resultsmentioning

confidence: 95%

Wave dissipation by ion cyclotron resonance in the solar corona

Marsch

2001

A&A

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Abstract. It has recently been suggested that small-scale reconnection occurring in the chromospheric network creates high-frequency Alfvén waves, and that these waves may represent the main energy source for the heating of the solar corona and generation of the solar wind. However, if these waves exist, they will be absorbed preferentially by the minor heavy ions with low gyrofrequencies, and thus it is unclear whether there is actually enough wave energy left over for the heating and acceleration of the major solar wind ions, namely protons and alpha particles, in the extended corona after the absorption by heavy ions (Cranmer 2000). We have studied this problem with the multi-fluid model presented by Tu & Marsch (2001), which includes the self-consistent treatment of the damping of the waves as well as the associated acceleration and heating of the ions. We found that if the wave power density is sufficiently large, say about 1000 nT 2 Hz −1 at 160 Hz and 2.5 R , then the wave absorption by a prominent minor ion such as O +5 is small, and most of the wave energy is left for absorption by protons. This occurs because the minor ions are quickly (within several gyroperiods) accelerated and then are induced to partially surfing the waves. However, if the wave power is too low, say lower than 10 nT 2 Hz −1 at 160 Hz and 2.5 R , then the damping of the wave power by the O +5 ions is severe, and little wave energy is left for protons.

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“…Hollweg (1999aHollweg ( , 1999bHollweg ( , 1999c) has pursued a test particle approach to the ion cyclotron interaction that clariÐes much of the complex kinetic physics. A rapidly growing number of publications have focused on many other issues concerned with ion cyclotron wave dissipation (e.g., Fletcher & Huber 1997 ;Leamon et al 1998a ;Marsch 1998 ;Czechowski et al 1998 ;Hu 1999 ;Hu & Habbal 1999 ;Kaghashvili 1999 ;Li et al 1999 ;Liewer, Velli, & Goldstein 1999 ;Tam & Chang 1999). This paper continues the investigation of heavy ion cyclotron resonances above polar coronal holes that was begun by Cranmer, Field, & Kohl (1999, hereafter CFK).…”

Section: Introductionmentioning

confidence: 90%

“…(1`d)@d. which yields a Kraichnan (1965) power spectrum, and Tu (1988) suggested d \ 3/2, which yields a Kolmogorov (1941) power spectrum (see also Hollweg 1987 ;Hu & Habbal 1999).…”

Section: Discussionmentioning

confidence: 99%

Ion Cyclotron Wave Dissipation in the Solar Corona: The Summed Effect of More than 2000 Ion Species

Cranmer

2000

ApJ

158

129

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In this paper the dissipation of ion cyclotron resonant waves in the extended solar corona is Alfve n examined in detail. For the Ðrst time, the wave damping arising from more than 2000 low-abundance ion species is taken into account. Useful approximations for the computation of coronal ionization equilibria for elements heavier than nickel are presented. Also, the Sobolev approximation from the theory of hot-star winds is applied to the resonant wave dissipation in the solar wind, and the surprisingly e †ective damping ability of "" minor ÏÏ ions is explained in simple terms. High-frequency (10È10,000 Hz) waves propagating up from the base of the corona are damped signiÐcantly when they resonate with ions having charge-to-mass ratios of about 0.1, and negligible wave power would then be available to resonate with higher charge-to-mass ratio ions at larger heights. This result conÐrms preliminary suggestions from earlier work that the waves that heat and accelerate the high-speed solar wind must be generated throughout the extended corona. The competition and eventual equilibrium between wave damping and wave replenishment may explain observed di †erences in coronal O VI and Mg X emission line widths.

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Resonant acceleration and heating of solar wind ions by dispersive ion cyclotron waves

Cited by 84 publications

References 37 publications

Physical parameters along the boundaries of a mid-latitude streamer and in its adjacent regions

Physical parameters along the boundaries of a mid-latitude streamer and in its adjacent regions

Wave dissipation by ion cyclotron resonance in the solar corona

Ion Cyclotron Wave Dissipation in the Solar Corona: The Summed Effect of More than 2000 Ion Species

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