The kinetic shell model of coronal heating and acceleration by ion cyclotron waves: 2. Inward and outward propagating waves

Isenberg, Philip A.

doi:10.1029/2001ja000176

Cited by 62 publications

(78 citation statements)

References 59 publications

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“…In particular, it remains to be shown to what extend the ion cyclotron waves proposed to heat the outer corona in numerous studies (Cranmer et al 1999c;Isenberg et al 2000Isenberg et al , 2001Isenberg 2001Isenberg , 2004Markovskii & Hollweg 2004;etc. ) are consistent with an isotropic non-thermal broadening velocity (which is known to be present in all layers of the solar atmosphere).…”

Section: Discussionmentioning

confidence: 99%

Sensitivity of solar off-limb line profiles to electron density stratification and the velocity distribution anisotropy

Raouafi¹,

Solanki²

2005

A&A

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The effect of the electron density stratification on the intensity profiles of the H i Ly-α line and the O vi and Mg x doublets formed in solar coronal holes is investigated. We employ an analytical 2-D model of the large scale coronal magnetic field that provides a good representation of the corona at the minimum of solar activity. We use the mass-flux conservation equation to determine the outflow speed of the solar wind at any location in the solar corona and take into account the integration along the line of sight (LOS). The main assumption we make is that no anisotropy in the kinetic temperature of the coronal species is considered. We find that at distances greater than 1 R from the solar surface the widths of the emitted lines of O vi and Mg x are sensitive to the details of the adopted electron density stratification. However, Ly-α, which is a pure radiative line, is hardly affected. The calculated total intensities of Ly-α and the O vi doublet depend to a lesser degree on the density stratification and are comparable to the observed ones for most of the considered density models. The widths of the observed profiles of Ly-α and Mg x are well reproduced by most of the considered electron density stratifications, while for the O vi doublet only few stratifications give satisfying results. The densities deduced from SOHO data result in O vi profiles whose widths and intensity ratio are relatively close to the values observed by UVCS although only isotropic velocity distributions are employed. These density profiles also reproduce the other considered observables with good accuracy. Thus the need for a strong anisotropy of the velocity distribution (i.e. a temperature anisotropy) is not so clear cut as previous investigations of UVCS data suggested. However, these results do not rule completely out the existence of some degree of anisotropy in the corona. The results of the present computations also suggest that the data can also be reproduced if protons, heavy ions and electrons have a common temperature, if the hydrogen and heavy-ion spectral lines are also non-thermally broadened by a roughly equal amount.

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Section: Discussionmentioning

confidence: 99%

Sensitivity of solar off-limb line profiles to electron density stratification and the velocity distribution anisotropy

Raouafi¹,

Solanki²

2005

A&A

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“…Upward propagating Alfven modes have been observed in the chromosphere (de Pontieu et al 2007), in the lower corona by Hinode (Ofman and Wang 2007;Okamoto et al 2007) and by ground-based detectors (Tomczyk et al 2007). The ion cyclotron heating mechanism proceeds by resonant wave particle interactions with Alfven waves, leading to heating of the solar corona (Isenberg 2001b(Isenberg , 2004. Recently Wind FC measurements have been used to statistically provide the first in situ evidence for ion heating via an Alfven-ion cyclotron resonant absorption process (Kasper et al 2008.…”

Section: Heating the Corona And Solar Windmentioning

confidence: 99%

Solar Wind Electrons Alphas and Protons (SWEAP) Investigation: Design of the Solar Wind and Coronal Plasma Instrument Suite for Solar Probe Plus

et al. 2015

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The Solar Wind Electrons Alphas and Protons (SWEAP) Investigation on SolarProbe Plus is a four sensor instrument suite that provides complete measurements of the electrons and ionized helium and hydrogen that constitute the bulk of solar wind and coronal plasma. SWEAP consists of the Solar Probe Cup (SPC) and the Solar Probe Analyzers (SPAN). SPC is a Faraday Cup that looks directly at the Sun and measures ion and electron fluxes and flow angles as a function of energy. SPAN consists of an ion and electron electrostatic analyzer (ESA) on the ram side of SPP (SPAN-A) and an electron ESA on the anti-ram side (SPAN-B). The SPAN-A ion ESA has a time of flight section that enables it to sort particles by their mass/charge ratio, permitting differentiation of ion species. SPAN-A and -B are rotated relative to one another so their broad fields of view combine like the seams on a baseball to view the entire sky except for the region obscured by the heat shield and covered by SPC. Observations by SPC and SPAN produce the combined field of view and measurement capabilities required to fulfill the science objectives of SWEAP and Solar Probe Plus. SWEAP measurements, in concert with magnetic and electric fields, energetic particles, and white light contextual imaging will enable discovery and understanding of solar wind acceleration and formation, coronal and solar wind heating, and particle acceleration in the inner heliosphere of the solar system. SPC and SPAN are managed by the SWEAP Electronics Module (SWEM), which distributes power, formats onboard data products, and serves as a single electrical interface to the spacecraft. SWEAP data products include ion and electron velocity distribution functions with high energy and angular resolution. Full resolution data are stored within the SWEM, enabling high resolution observations of structures such as shocks, reconnection events, and other transient structures to be selected for download after the fact. This paper describes the implementation of the SWEAP Investigation, the driving requirements for the suite, expected performance of the instruments, and planned data products, as of mission preliminary design review.

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“…Laitinen et al (2003) have recently discussed various approaches employed for an explicit incorporation of the process of ion-cyclotron damping into kinetic (e.g. Isenberg 2001), semi-kinetic (e.g. Vocks & Marsch 2001) or hybrid (e.g.…”

Section: Introductionmentioning

confidence: 99%

A simple analytical expression for the power spectrum of cascading Alfvén waves in the solar wind

Vainio

Laitinen

Fichtner

2003

A&A

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Abstract. Alfvén wave transport in the solar wind, including non-linear spectral energy transfer, is studied. We present numerical solutions of wave transport using a diffusive flux function previously introduced for spectral energy transfer, and compare it with the analytical solution obtained for a convective flux function. The two models of cascading produce very similar behavior of a power spectrum initially of 1/ f -form at the solar surface, provided that the cascading constants are tuned to produce the same spectral flux in the inertial range. We present an analytical expression for the power spectrum of the diffusively-cascading Alfvén waves in the solar wind derived from a solution of the wave transport equation and show that it compares well with the exact solutions. Our expression enables (semi) analytical evaluation of the cyclotron heating rate, the wave pressure gradient, and the energetic-particle mean free path related to the Alfvén waves in the corona and solar wind.

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The kinetic shell model of coronal heating and acceleration by ion cyclotron waves: 2. Inward and outward propagating waves

Cited by 62 publications

References 59 publications

Sensitivity of solar off-limb line profiles to electron density stratification and the velocity distribution anisotropy

Sensitivity of solar off-limb line profiles to electron density stratification and the velocity distribution anisotropy

Solar Wind Electrons Alphas and Protons (SWEAP) Investigation: Design of the Solar Wind and Coronal Plasma Instrument Suite for Solar Probe Plus

A simple analytical expression for the power spectrum of cascading Alfvén waves in the solar wind

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