Effect of local interstellar medium hydrogen fractional ionization on the distant solar wind and interface region

Баранов, В. Б.; Malama, Yu. G.

doi:10.1029/95ja00655

Cited by 122 publications

(61 citation statements)

References 11 publications

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“…Secondary interstellar atoms, which are a result of charge exchange of the original interstellar H atoms and solar wind protons, disturb the interstellar gas upwind the bow shock. Detail studies of mutual influences of charge and neutral components in the heliospheric interface were done in Baranov and Malama (1993,1995, 1996, Baranov et al (1998), Izmodenov et al (1999Izmodenov et al ( , 2000Izmodenov et al ( , 2001. However, these papers were mainly focused on the upwind region.…”

Section: Introductionmentioning

confidence: 99%

A model for the tail region of the heliospheric interface

Izmodenov

Alexashov

2003

Astron. Lett.

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Physical processes in the tail of the solar wind interaction region with the partially ionized local interstellar medium are investigated in a framework of the self-consistent kinetic-gas dynamic model. It is shown that the charge exchange process of the hydrogen atoms with the plasma protons results in suppression of the gas dynamic instabilities and disappearance the contact discontinuity at sufficiently ( 3000 AU) large distances from the Sun. The solar wind plasma temperature decreases and, ultimately, the parameters of the plasma and hydrogen atoms approach to the corresponding parameters of the unperturbed interstellar medium at large heliocentric distances.

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Section: Introductionmentioning

confidence: 99%

A model for the tail region of the heliospheric interface

Izmodenov

Alexashov

2003

Astron. Lett.

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“…a background magnetic field B LISM exists which is oriented parallel to the stagnation line (i.e., according to an MHD interaction model with B LISM V LISM as treated, e.g., by Baranov & Malama 1995;Pogorelov & Matsuda 1998;or Ratkiewicz & McKenzie 2003), one then can assume that Alfvén waves are excited by this free energy which then propagate upstream and downstream of the plasma flow. The free energy of newly injected protons stemming from the bulk of the H-atom distribution function can then be assumed to be pumped into the wave field at the injection wave number fulfilling the resonance conditions and given in the bulk plasma system by:…”

Section: Outlook: Competing Proton Relaxation Processes In Heliosphermentioning

confidence: 99%

A kinetic control of the heliospheric interface hydrodynamics of charge-exchanging fluids

Fahr

Bzowski

2004

A&A

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Abstract.It is well known that the Solar System is presently moving through a partially ionized local interstellar medium. This gives rise to a counter-flow situation requiring a consistent description of behaviour of the two fluids -ions and neutral atoms -which are dynamically coupled by mutual charge exchange processes. Solutions to this problem have been offered in the literature, all relying on the assumption that the proton fluid, even under evidently nonequilibrium conditions, can be expected to stay in a highly-relaxated distribution function given by mono-Maxwellians shifted by the local proton bulk velocity. Here we check the validity of this assumption, calculating on the basis of a Boltzmann-kinetic approach the actually occurring deviations. As we show, especially for low degrees of ionization, ξ ≤ 0.3, both the H-atoms and protons involved do generate in the heliospheric interface clearly pronounced deviations from shifted Maxwellians with asymmetrically shaped distribution functions giving rise to non-convective transport processes and heat conduction flows. Also in the inner heliosheath region and in the heliotail deviations of the proton distribution from the hydrodynamic one must be expected. This sheds new light on the correctness of current calculations of H-atom distribution functions prevailing in the inner heliosphere and also of the Lyman-α absorption features in stellar spectra due to the presence of the hydrogen wall atoms. Deviations from LTE-functions would be even more pronounced in magnetic interfaces, which via CGL-effects cause temperature anisotropies to arise.

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“…The Lyman-α diagnostic for stellar mass loss rates Baranov & Malama (1995) showed that charge exchange processes between solar wind protons and neutral hydrogen atoms in the local interstellar medium (ISM) produce a population of heated, decelerated hydrogen atoms concentrated in the interstellar upwind direction, the so-called "hydrogen wall". These calculations and those in subsequent models of Zank et al (1996), Izmodenov et al (1999), and Müller et al (2001) allowed Wood et al (2001) to computeṀ for α Cen.…”

Section: Why Mass Loss Rates Are Needed For the Sun And Cool Dwarf Starsmentioning

confidence: 99%

The solar wind in time

Linsky¹,

Wood²,

Redfield³

2011

Proc. IAU

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Abstract. We describe our method for measuring mass loss rates of F-M main sequence stars with high-resolution Lyman-α line profiles. Our diagnostic is the extra absorption on the blue side the interstellar hydrogen absorption produced by neutral hydrogen gas in the hydrogen walls of stars. For stars with low X-ray fluxes, the correlation of observed mass loss rate with X-ray surface flux and age predicts the solar wind mass flux between 700 Myr and the present.Keywords. ISM:lines and bands, ISM:magnetic fields, solar wind, stars:winds, Sun: UV radiation, ultraviolet:ISM Why mass loss rates are needed for the Sun and cool dwarf starsUltraviolet spectroscopy is an important tool for measuring mass loss rates (Ṁ) of massive stars, late-type giants, and premain sequence stars whenṀ> 10 −10 M yr −1 . By comparison, the solar mass loss rate measured by space experiments is far smaller, about 2 × 10 −14 M yr −1 . Until 10 years ago, there were no measured values ofṀ for main sequence stars cooler than about spectral type A because there were no spectral or other diagnostics capable of measuringṀ far smaller than 10 −10 M yr −1 . While mass loss rates similar to the Sun do not significantly reduce a star's mass and thus nuclear evolution during its lifetime (see below), accurate measurements ofṀ are needed for many reasons: (1) the torque exerted by even weak stellar winds reduces the stellar rotation rate and thus the magnetic dynamo and stellar activity, (2) knowledge oḟ M(t) for the young Sun is important for understanding the evolution of the atmospheres of solar system planets like Mars that have lost their magnetic fields, and (3) the discovery of exopolanets close to their host stars highlights the need to predict the properties of stellar winds that impact the atmospheres of these exoplanets. Since we cannot measurė M back in time, it is critical to find a reliable diagnostic to measureṀ for solar-mass stars with a range of ages and coronal properties in order to scale to the young Sun. Unfortunately, theoretical estimates ofṀ are controversial, an empirical relationship betweenṀ and X-ray flux was not previously known, and no space probe will enter an astrosphere to directly measureṀ for a very long time.

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Effect of local interstellar medium hydrogen fractional ionization on the distant solar wind and interface region

Cited by 122 publications

References 11 publications

A model for the tail region of the heliospheric interface

A model for the tail region of the heliospheric interface

A kinetic control of the heliospheric interface hydrodynamics of charge-exchanging fluids

The solar wind in time

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