Shock-free Deceleration of the Solar Wind?

Wallis, M. K.

doi:10.1038/physci233023a0

Cited by 62 publications

(46 citation statements)

References 8 publications

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“…The SW flow, on the other hand, is decelerated due to its interaction with the HP, charge exchange with interstellar neutral atoms, and by the LISM counter-pressure in the heliotail region. Since the neutral hydrogen (H) density in the LISM is greater that the proton density, resonant charge exchange between ions and neutral ions plays a major role in the SW-LISM interactions (Blum & Fahr 1969;Holzer 1977;Wallis 1971Wallis , 1975. In particular, the SW in the tail is decelerated and cooled down by charge exchange until the heliotail disappears at a few tens of thousands of AU.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional Features of the Outer Heliosphere Due to Coupling between the Interstellar and Heliospheric Magnetic Field. V. The Bow Wave, Heliospheric Boundary Layer, Instabilities, and Magnetic Reconnection

Pogorelov

Heerikhuisen

Roytershteyn

et al. 2017

ApJ

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The heliosphere is formed due to interaction between the solar wind (SW) and local interstellar medium (LISM). The shape and position of the heliospheric boundary, the heliopause, in space depend on the parameters of interacting plasma flows. The interplay between the asymmetrizing effect of the interstellar magnetic field and charge exchange between ions and neutral atoms plays an important role in the SW-LISM interaction. By performing three-dimensional, MHD plasma / kinetic neutral atom simulations, we determine the width of the outer heliosheath -the LISM plasma region affected by the presence of the heliosphere -and analyze quantitatively the distributions in front of the heliopause.It is shown that charge exchange modifies the LISM plasma to such extent that the contribution of a shock transition to the total variation of plasma parameters becomes small even if the LISM velocity exceeds the fast magnetosonic speed in the unperturbed medium. By performing adaptive mesh refinement simulations, we show that a distinct boundary layer of decreased plasma density and enhanced magnetic field should be observed on the interstellar side of the heliopause. We show that this behavior is in agreement with the plasma oscillations of increasing frequency observed by the plasma wave instrument onboard Voyager 1. We also demonstrate that Voyager observations in the inner heliosheath between the heliospheric termination shock and the heliopause are consistent with dissipation of the heliospheric magnetic field. The choice of LISM parameters in this analysis is based on the simulations that fit observations of energetic neutral atoms performed by IBEX.

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Section: Introductionmentioning

confidence: 99%

Three-dimensional Features of the Outer Heliosphere Due to Coupling between the Interstellar and Heliospheric Magnetic Field. V. The Bow Wave, Heliospheric Boundary Layer, Instabilities, and Magnetic Reconnection

Pogorelov

Heerikhuisen

Roytershteyn

et al. 2017

ApJ

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“…The idea was that mass-loading of the solar wind could occur quickly enough to cause a strong shock at a singularity in that one dimensional solution. In contrast, a weak or nonexistent shock was anticipated by Wallis [1971Wallis [ , 1973. The current consensus among modelers is that a weak bow shock appears in two-and three-dimensional MHD calculations [e.g., Schmidt The theory and simulation work on cometary bow shocks falls into four categories: single fluid, multiple fluid, semikinetic, and kinetic.…”

Section: Introductionmentioning

confidence: 99%

Bow shock analysis at comets Halley and Grigg‐Skjellerup

Coates¹,

Mazelle²,

Neubauer³

1997

J. Geophys. Res.

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Abstract. The interaction of an active comet with the solar wind is effected by the pickup of heavy cometary ions over extended regions of space. It was predicted before any spacecraft encounters with comets that a bow shock would form at a critical point in the mass-loaded flow. Here we present an analysis of the results from Giotto's encounters of comets Halley and Grigg-Skjellerup on the plasma structure of the bow shock regions at the two comets. This is achieved in a joint analysis of data on solar wind and cometary ions, magnetic field, and electrons. We find that these mass-loading shocks are among the most complex in the solar system with heavy cometary ions dominating the component pressures. Results of Mach number calculations at Halley support earlier interpretations that bow shocks were, indeed, seen with possible solar wind disturbance inbound. At Grigg-Skjellerup, Mach number results support the interpretation of a "wave" inbound and a "shock" outbound; both features also occur near to the expected location for a bow shock. A weak correlation between magnetic field strength and electron density is noted at the Grigg-Skjellerup outbound shock in agreement with quasi-perpendicular hybrid simulations.

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“…The first models were formulated by Wallis [1971] and Holzer [1972]. Since then, increasingly sophisticated Monte Carlo [Baranov and Malama, 1993; .…”

Section: Introductionmentioning

confidence: 99%

The heliosphere‐interstellar medium interaction: One shock or two?

Richardson¹

1997

Geophysical Research Letters

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Abstract.The issue of whether a shock forms in the interstellar medium as it approaches the heliopause has not been settled. Observations generally show that the local interstellar medium is slighfiy supersonic with respect to a stationary (constant distance from the Sun) heliopause. The solar wind dynamic pressure varies over the solar cycle, causing the heliopause distance to move inward and outward. This work shows that the heliopause speeds may be large compared to the speed of the interstellar medium. This leads to the scenario where the interstellar medium is supersonic with respect to the heliopause when the heliopause moves outward (the declining phase of the solar cycle) and subsonic the rest of the time. A shock would form when the heliopause moves outwards and dissipate when the heliopause moves inwards. The heliospheric radio emission is shown to occur at times when the heliopause moves outwards and thus may be related to the formation of the shock in the interstellar medium. This work leads to two testable predictions: 1) that the heliospheric radio emissions will intensify when the solar wind pressure increases and 2) the temperature of the interstellar neutrals will fluctuate over a solar cycle with larger temperatures when there is a shock in the interstellar medium.

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Shock-free Deceleration of the Solar Wind?

Cited by 62 publications

References 8 publications

Three-dimensional Features of the Outer Heliosphere Due to Coupling between the Interstellar and Heliospheric Magnetic Field. V. The Bow Wave, Heliospheric Boundary Layer, Instabilities, and Magnetic Reconnection

Three-dimensional Features of the Outer Heliosphere Due to Coupling between the Interstellar and Heliospheric Magnetic Field. V. The Bow Wave, Heliospheric Boundary Layer, Instabilities, and Magnetic Reconnection

Bow shock analysis at comets Halley and Grigg‐Skjellerup

The heliosphere‐interstellar medium interaction: One shock or two?

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