<i>INTERSTELLAR BOUNDARY EXPLORER</i>MEASUREMENTS AND MAGNETIC FIELD IN THE VICINITY OF THE HELIOPAUSE

Pogorelov, N. V.; Heerikhuisen, J.; Zank, G. P.; Borovikov, S. N.; Frisch, P. C.; McComas, D. J.

doi:10.1088/0004-637x/742/2/104

Cited by 66 publications

(52 citation statements)

References 56 publications

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“…Its departure from circularity in the azimuthal range 210 • -330 • is due to the draping of the ISMF around the heliopause in the ENA source region beyond the heliopause (Schwadron et al 2009;Pogorelov et al 2011). We note that this elongation is perpendicular to the nose direction at 0 • azimuth in the rotated frame of Figure 11 and in the same direction as the elongation of the ribbon observed in both the elliptical fit (Figure 3) and the results of the statistical analysis ( Figure 5).…”

Section: Testing Of Modelssupporting

confidence: 51%

“…Results of magnetohydrodynamic (MHD) simulations of the ISM-heliospheric interaction (e.g., Pogorelov et al 2011) are consistent with (1) the ribbon center as the likely direction of the ISMF and (2) the arc traced by the ribbon as the result of perturbation of the ISMF geometry by the heliosphere. The perturbed ISMF magnetic field direction B P resulting in the ribbon is uniquely perpendicular to the radial line-of-sight vectorr from the inner heliosphere, i.e., B P ·r ≈ 0 (e.g., Schwadron et al 2009).…”

Section: Introductionmentioning

confidence: 61%

“…The statistical variation σ C listed in Table 1, which describes the uncertainty of the circular fit to the ribbon peak locations φ C (θ ), provides a quantitative constraint on the spatial and temporal variability of these underlying processes, which might arise from, for example, the draping geometry of the ISMF over the heliosphere (McComas et al 2009a;Schwadron et al 2009;Heerikhuisen et al 2010;Chalov et al 2010;Pogorelov et al 2011), oscillation of the outer heliosheath configuration in response to solar cycle variations , and turbulent magnetic field and plasma flow fluctuations in the ISM (Armstrong et al 1995;Spangler et al 2011).…”

Section: Spatial Coherence Of the Ribbon Emission Regionmentioning

confidence: 99%

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CIRCULARITY OF THEINTERSTELLAR BOUNDARY EXPLORERRIBBON OF ENHANCED ENERGETIC NEUTRAL ATOM (ENA) FLUX

Funsten

Demajistre

Frisch

et al. 2013

ApJ

132

153

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As a sharp feature in the sky, the ribbon of enhanced energetic neutral atom (ENA) flux observed by the Interstellar Boundary Explorer (IBEX) mission is a key signature for understanding the interaction of the heliosphere and the interstellar medium through which we are moving. Over five nominal IBEX energy passbands (0.7, 1.1, 1.7, 2.7, and 4.3 keV), the ribbon is extraordinarily circular, with a peak location centered at ecliptic (λ RC , β RC ) = (219.• 2 ± 1.• 3, 39.• 9 ± 2.• 3) and a half cone angle of φ C = 74.• 5 ± 2.• 0. A slight elongation of the ribbon, generally perpendicular to the ribbon center-heliospheric nose vector and with eccentricity ∼0.3, is observed over all energies. At 4.3 keV, the ribbon is slightly larger and displaced relative to lower energies. For all ENA energies, a slice of the ribbon flux peak perpendicular to the circular arc is asymmetric and systematically skewed toward the ribbon center. We derive a spatial coherence parameter δ C 0.014 that characterizes the spatial uniformity of the ribbon over its extent in the sky and is a key constraint for understanding the underlying processes and structure governing the ribbon ENA emission.

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Section: Testing Of Modelssupporting

confidence: 51%

Section: Introductionmentioning

confidence: 61%

Section: Spatial Coherence Of the Ribbon Emission Regionmentioning

confidence: 99%

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CIRCULARITY OF THEINTERSTELLAR BOUNDARY EXPLORERRIBBON OF ENHANCED ENERGETIC NEUTRAL ATOM (ENA) FLUX

Funsten

Demajistre

Frisch

et al. 2013

ApJ

132

153

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“…Since the draping of the LISM magnetic field is a function of distance from the heliopause (e.g., Grygorczuk et al 2011;Pogorelov et al 2011;Zirnstein et al 2015a), the energy of the parent SW and ENA distribution may affect the distances at which the majority of ribbon ENAs (observed at 1 au) originate. We are not attempting to reproduce the IBEX results, but rather attempt to understand the effects of SW speed and ENA energy on the geometry of the secondary ENA ribbon, in the absence of time-dependent and asymmetric SW effects.…”

Section: Comparing Simulated and Ibex Ribbon Geometrymentioning

confidence: 99%

Effects of solar wind speed on the secondary energetic neutral source of the Interstellar Boundary Explorer ribbon

Zirnstein

Funsten

Heerikhuisen

et al. 2016

A&A

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The Interstellar Boundary EXplorer (IBEX) ribbon is an intense energetic neutral atom (ENA) emission feature encircling the sky, spanning energies ≤0.5-6 keV. The ribbon may be produced by the "secondary ENA" mechanism, where ENAs emitted from a source plasma population inside the heliosphere propagate outside the heliopause, undergo two charge-exchange events, and become secondary ENAs that may be directed back toward Earth and detected by IBEX. In this scenario, the source plasma population is governed by the interaction of the solar wind (SW) with the interstellar medium and is thus sensitive to the global SW properties. Moreover, this scenario predicts that the distance to the source of secondary ENAs depends on the ENA energy and SW speed, which in turn may affect the shape of the ribbon. In this paper, we use a computational model of the heliosphere with simplified SW boundary conditions to analyze the influence of ENA energy and SW speed, independent of time and latitude, on the global spatial and geometric properties of the ribbon. We find a strong dependence of the simulated ribbon energy spectrum and spatial symmetry on SW speed and ENA energy, and only a slight dependence on ribbon geometry. Our results suggest a significant number of primary ENAs from the inner heliosheath may contribute to the pickup ion source population outside the heliopause, depending on the ENA energy and SW speed. The lack of variation in the simulated ribbon center as a function of ENA energy and SW speed, in contrast to the observations, implies that the asymmetry of the SW plays an important role in determining the position of the ribbon. Comparisons to the IBEX data also signify the ribbon's dependence on the properties of the local interstellar medium, particularly the interstellar magnetic field.

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“…The background heliosphere is based on an MHD description for the ionized plasma, kinetically coupled through chargeexchange collisions to the ambient neutral hydrogen that is calculated via a Monte Carlo approach (see Pogorelov et al 2011). This approach allows for arbitrary phase-space distributions of H. The protons also have a complex distribution function, since charge-exchange gives rise to PUIs with a velocity distribution different from the "core" plasma (Vasyliunas & Siscoe 1976).…”

Section: Improved Simulationsmentioning

confidence: 99%

ENERGETIC NEUTRAL ATOMS MEASURED BY THEINTERSTELLAR BOUNDARY EXPLORER(IBEX): EVIDENCE FOR MULTIPLE HELIOSHEATH POPULATIONS

Desai

Allegrini

Bzowski

et al. 2013

ApJ

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Energetic neutral atoms (ENAs) observed by the Interstellar Boundary Explorer (IBEX) provide powerful diagnostics about the origin of the progenitor ion populations and the physical mechanisms responsible for their production. In this paper, we extend the work of Desai et al. and Fuselier et al. and combine and compare ENA spectra from the first 3 yr of observations by the IBEX-Hi and -Lo ENA imagers along the lines-of-sight (LOSs) from the inner heliosphere through to the locations of Voyager 1 and 2 with results from an updated physics-based model of the three-dimensional heliosphere and its constituent ion populations. Our results show that (1) IBEX ENA fluxes and spectra above ∼0.7 keV measured along the LOSs of the Voyagers are consistent with several models in which the parent pickup ion (PUI) populations originate in the inner heliosheath, and (2) a significant fraction of lower energy ENAs between ∼0.1-0.5 keV may originate from interstellar neutral gas charge-exchanging with a nonthermalized (hot) population of PUIs in the outer heliosheath beyond the heliopause. We discuss the implications of ENAs observed by IBEX originating from distinct parent populations as well as from two distinct locations in the heliospheric interface. These results indicate that ENA spectral measurements at various energies can be used to remotely probe distinct physical processes operating in vastly different regions of the distant heliosphere.

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INTERSTELLAR BOUNDARY EXPLORERMEASUREMENTS AND MAGNETIC FIELD IN THE VICINITY OF THE HELIOPAUSE

Cited by 66 publications

References 56 publications

CIRCULARITY OF THEINTERSTELLAR BOUNDARY EXPLORERRIBBON OF ENHANCED ENERGETIC NEUTRAL ATOM (ENA) FLUX

CIRCULARITY OF THEINTERSTELLAR BOUNDARY EXPLORERRIBBON OF ENHANCED ENERGETIC NEUTRAL ATOM (ENA) FLUX

Effects of solar wind speed on the secondary energetic neutral source of the Interstellar Boundary Explorer ribbon

ENERGETIC NEUTRAL ATOMS MEASURED BY THEINTERSTELLAR BOUNDARY EXPLORER(IBEX): EVIDENCE FOR MULTIPLE HELIOSHEATH POPULATIONS

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