Filtration of interstellar hydrogen in the two‐shock heliospheric interface: Inferences on the local interstellar cloud electron density

Izmodenov, Vladislav; Geiss, J.; Lallement, R.; Gloeckler, G.; Баранов, В. Б.; Malama, Yu. G.

doi:10.1029/1998ja900122

Cited by 82 publications

(61 citation statements)

References 39 publications

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“…Therefore, differences between the observed He parameters and those of O and H will set very tight constraints on the physical processes in the heliospheric interface region that lead to filtration of most of the LIC species, except for He, when they enter the heliosphere (Izmodenov et al 1999;Müller et al 2000). Having established the amount of filtration, the observation of elemental abundances of several LIC species, such as He, H and O, inside the heliosphere together with detailed modeling can be used to deduce a LIC abundance pattern for the neutral gas component (Izmodenov et al 1999;Müller et al 2000;Izmodenov et al 2004). Such results can then be compared with quantitative predictions made for the ionization state of the LIC based on modeling of the radiation environment of our galactic neighborhood (Frisch & Slavin 1996;Slavin & Frisch 2002).…”

Section: Conclusion and Future Perspectivesmentioning

confidence: 99%

“…its bulk flow velocity v He , longitude λ and latitude β of the inflow direction, temperature T He and density n He , as it enters the heliosphere unimpeded. Conversely, the abundance of H and O, along with other species, is significantly depleted, their speed decreased, and their temperature increased, through charge exchange in the heliospheric interface (Fahr 1991;Ruciński et al 1993;Izmodenov et al 1999;Müller et al 2000;Izmodenov et al 2004). Thus He can provide a solid basis for the study of the filtration effects at the heliospheric boundary through comparison with H and O, a prerequisite for the determination of the LIC composition from observations inside the heliosphere.…”

Section: Introduction and Historical Contextmentioning

confidence: 99%

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Synopsis of the interstellar He parameters from combined neutral gas, pickup ion and UV scattering observations and related consequences

Möbius¹,

Bzowski

Chalov

et al. 2004

A&A

190

133

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Abstract.A coordinated effort to combine all three methods that are used to determine the physical parameters of interstellar gas in the heliosphere has been undertaken. In order to arrive at a consistent parameter set that agrees with the observations of neutral gas, pickup ions and UV backscattering we have combined data sets from coordinated observation campaigns over three years from 1998 through 2000. The key observations include pickup ions with ACE and Ulysses SWICS, neutral atoms with Ulysses GAS, as well as UV backscattering at the He focusing cone close to the Sun with SOHO UVCS and at 1 AU with EUVE. For the first time also the solar EUV irradiance that is responsible for photo ionization was monitored with SOHO CELIAS SEM, and the He I 58.4 nm line that illuminates He was observed simultaneously with SOHO SUMER. The solar wind conditions were monitored with SOHO, ACE, and WIND. Based on these data the modeling of the interstellar gas and its secondary products in the heliosphere has resulted in a consistent set of interstellar He parameters with much reduced uncertainties, which satisfy all observations, even extended to earlier data sets. It was also established that a substantial ionization in addition to photo ionization, most likely electron impact, is required, with increasing relative importance closer to the Sun. Furthermore, the total combined ionization rate varies significantly with solar latitude, requiring a fully three dimensional and time dependent treatment of the problem.

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Section: Conclusion and Future Perspectivesmentioning

confidence: 99%

Section: Introduction and Historical Contextmentioning

confidence: 99%

Synopsis of the interstellar He parameters from combined neutral gas, pickup ion and UV scattering observations and related consequences

Möbius¹,

Bzowski

Chalov

et al. 2004

A&A

190

133

View full text Add to dashboard Cite

show abstract

“…Baranov & Malama 1993;Izmodenov et al 1999;Alexashov et al 2000Alexashov et al , 2004aMyasnikov et al 2000;Zaitsev & Izmodenov 2001;Izmodenov & Alexashov 2003;Izmodenov et al 2003a,b;; for reviews see Izmodenov 2003Izmodenov , 2004 by introducing 11 year sinusoidal variations of the solar wind in the model. The goal of this paper is to explore theoretical aspects of nonstationary interaction of the solar wind and the local interstellar cloud.…”

Section: Modelmentioning

confidence: 99%

Solar cycle influence on the interaction of the solar wind with Local Interstellar Cloud

Izmodenov

Malama

Рудерман

2005

A&A

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Abstract. We present results of a new time-dependent kinetic model of the H atom penetration through the solar windinterstellar medium interaction region. A kinetic 6D (time, two dimensions in space, and three dimensions in velocity-space) equation for interstellar H atoms was solved self-consistently with time-dependent Euler equations for the solar wind and interstellar charged components. We study the response of the interaction region to 11-year solar cycle variations of the solar wind dynamic pressure. It is shown that the termination shock location varies within ±7 AU, the heliopause variation is ∼4 AU, and the bow shock variation is negligible. At large heliocentric distances, the solar cycle induces 10-12% fluctuations in the number density of both primary and secondary interstellar H atoms and atoms created in the inner heliosheath. We underline the kinetic behavior of the fluctuations of the H atom populations. Closer to the Sun the fluctuations increase up to 30-35% at 5 AU due to solar cycle variation of the charge exchange rate. Solar cycle variations of interstellar H atoms in the heliospheric interface and within the heliosphere may have major importance for the interpretation of H atom observations inside the heliosphere.

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“…The very broad, weak Lyα absorption that this population produces is much harder to detect than the stronger hydrogen wall signature. In upwind and sidewind directions, the inner heliosheath is too narrow for there to be detectable heliosheath absorption; in downwind directions, line-of-sight distances through this region are longer and the absorption is detectable through its kinematic properties (Izmodenov et al 1999b;Wood et al 2007).…”

Section: Anomalous Cosmic Rays and Heliospheric Asymmetriesmentioning

confidence: 99%

“…The basic understanding of the related heliosphere-LIC interaction has been summarized in early reviews (Axford 1972;Fahr 1974;Holzer 1989;Thomas 1978), as well as con-temporary discussions (Fahr 1991;Baranov and Malama 1993;Ruciński et al 1993;Zank et al 1996;Izmodenov et al 1999aFahr et al 2000;Müller et al 2000;Heerikhuisen et al 2006).…”

Section: Hydrogenmentioning

confidence: 99%

The Galactic Environment of the Sun: Interstellar Material Inside and Outside of the Heliosphere

et al. 2009

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Interstellar material (ISMa) is observed both inside and outside of the heliosphere. Relating these diverse sets of ISMa data provides a richer understanding of both the interstellar medium and the heliosphere. The galactic environment of the Sun is dominated by warm, low-density, partially ionized interstellar material consisting of atoms and dust grains. The properties of the heliosphere are dependent on the pressure, composition, radiation field, ionization, and magnetic field of ambient ISMa. The very low-density interior of the Local Bubble, combined with an expanding superbubble shell associated with star formation in the Scorpius-Centaurus Association, dominate the properties of the local interstellar medium (LISM). Once the heliosphere boundaries and interaction mechanisms are understood, interstellar gas, dust, pickup ions, and anomalous cosmic rays inside of the heliosphere can be directly compared to ISMa outside of the heliosphere. Our understanding of ISMa at the Sun is further enriched when the circumheliospheric interstellar material is compared to observations of other nearby ISMa and the overall context of our galactic environment. The IBEX mission will map the interaction region between the heliosphere and ISMa, and improve the accuracy of comparisons between ISMa inside and outside the heliosphere.

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Filtration of interstellar hydrogen in the two‐shock heliospheric interface: Inferences on the local interstellar cloud electron density

Cited by 82 publications

References 39 publications

Synopsis of the interstellar He parameters from combined neutral gas, pickup ion and UV scattering observations and related consequences

Synopsis of the interstellar He parameters from combined neutral gas, pickup ion and UV scattering observations and related consequences

Solar cycle influence on the interaction of the solar wind with Local Interstellar Cloud

The Galactic Environment of the Sun: Interstellar Material Inside and Outside of the Heliosphere

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