Magnetized Jets Driven by the Sun: The Structure of the Heliosphere Revisited

Opher, M.; Drake, J. F.; Zieger, B.; Gombosi, T. I.

doi:10.1088/2041-8205/800/2/l28

Cited by 129 publications

(207 citation statements)

References 44 publications

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“…Recently, we have shown that the heliosheath ions are the source of INCA/ENA, whereas the combined use of > 5.2 keV ENAs and in-situ LECP ions, have demonstrated that the heliosphere responds promptly, withiñ 2-3 years, to outward propagating solar wind changes in both the nose and anti-nose directions [25]. Taking into account the V1 measurement of a~0.5 nT [26] interstellar magnetic field (ISMF) and the high plasma beta in the heliosheath [13], we have concluded that the heliosphere behaves as a diamagnetic bubble with little substantial tail-like features, consistent with recent modelling [27], [28], [29], [30]. Although different interpretations and models of the V1 measurements exist, showing that the spacecraft may not have exited to interstellar space [31], [32], a fact that can possibly point to a heliosheath with different magnetic properties [33] other than a "diamagnetic bubble", such a view does not preclude the rough nose-"anti-nose" symmetry shown in our recent analysis [25].…”

Section: Introductionsupporting

confidence: 84%

“…In other recent studies [30] the "Parker-bubble" was tested and a heliosphere with a symmetric termination shock was concluded when using an interstellar magnetic field close enough (0.44 nT), comparable to the measured one (~0.5 nT). Finally, a very recent and challenging model [27], [28] depicts a view of the heliosphere with turbulent jets deflected into the tail region by the interstellar wind (a "croissant-type" heliosphere), but not strong enough to drive a "comet-type" tail.…”

Section: Discussionmentioning

confidence: 99%

“…Consequently, the heliosphere bubble can inflate with time in either the anti-nose direction (as "tail" models suggest) or along the direction of the interstellar magnetic field (as in the Parker-Bubble model). The recent model that shows a view of the heliosphere with two prominent polar jets [27], [28], provides one of the possible ways through which the solar wind input can be evacuated from the heliosphere.…”

Section: Global Ena Emissions Over Solar Cycles 23 and 24mentioning

confidence: 99%

“…[42], [43]), recent models show that the average magnetosonic speed towards the tail can be as low as~50 km/sec (e.g. [27]) and as high as~140 km/sec (e.g. [22]).…”

Section: Recovery Times Of Enas Over the Onset Of Solar Cycle 24 And mentioning

confidence: 99%

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Response times of Cassini/INCA > 5.2 keV ENAs and Voyager ions in the heliosheath over the solar cycle

Dialynas

Krimigis

Mitchell

et al. 2017

J. Phys.: Conf. Ser.

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Abstract. Both a magnetosphere-like tail and a bubble model of the heliosphere were posited by E. N. Parker in 1961. Recently, we showed that heliosheath ions are the source of > 5.2 keV Energetic Neutral Atoms (ENA), whose images of the heliosphere exhibit a rough nose to antinose (tail) global symmetry that resembles a diamagnetic bubble. The comparison between energetic neutral atom (ENA) global images of the helioshphere obtained with the Ion and Neutral Camera (INCA) on board Cassini and ions measured in-situ by the Low Energy Charged Particle experiment (LECP) on board Voyager 1 and 2 (V1/V2) in overlapping energy bands over an 11-year period shows that the heliosphere responds promptly, within~2-3 years, to outward propagating solar wind changes in both the nose and tail directions. Here we focus on the recovery of solar cycle 24 and the response times of > 5.2 keV ENAs to show that this 2-3-year time delay is consistent with a "tail" of~80-120 AU. This preliminary rough calculation is generally consistent with lower energy ENA data (E < 6 keV, from the IBEX-Lo and IBEX-Hi) and is supported by recent modelling of the heliosphere.

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Section: Introductionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Section: Global Ena Emissions Over Solar Cycles 23 and 24mentioning

confidence: 99%

“…[42], [43]), recent models show that the average magnetosonic speed towards the tail can be as low as~50 km/sec (e.g. [27]) and as high as~140 km/sec (e.g. [22]).…”

Section: Recovery Times Of Enas Over the Onset Of Solar Cycle 24 And mentioning

confidence: 99%

See 2 more Smart Citations

Response times of Cassini/INCA > 5.2 keV ENAs and Voyager ions in the heliosheath over the solar cycle

Dialynas

Krimigis

Mitchell

et al. 2017

J. Phys.: Conf. Ser.

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“…Based on a survey of outer heliospheric models (e.g., Pogorelov et al 2007Pogorelov et al , 2013Izmodenov et al 2009;Opher et al 2009Opher et al , 2015, a proton outbound along the heliographic equator will travel roughly an additional 200 au through the IHS to the pole as compared to a proton traveling directly poleward. For a flow speed in the IHS of ∼150 km s −1 (based on Voyager 2 observations; Burlaga et al 2009), this corresponds to a travel time difference of ∼6.5 years, or more than half a solar cycle.…”

Section: Propagation Of Variations Along Streamlinesmentioning

confidence: 99%

Tracking the Solar Cycle Through Ibex Observations of Energetic Neutral Atom Flux Variations at the Heliospheric Poles

Reisenfeld

Bzowski

Funsten

et al. 2016

ApJ

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With seven years of Interstellar Boundary Explorer (IBEX) observations, from 2009 to 2015, we can now trace the time evolution of heliospheric energetic neutral atoms (ENAs) through over half a solar cycle. At the north and south ecliptic poles, the spacecraft attitude allows for continuous coverage of the ENA flux; thus, signal from these regions has much higher statistical accuracy and time resolution than anywhere else in the sky. By comparing the solar wind dynamic pressure measured at 1 au with the heliosheath plasma pressure derived from the observed ENA fluxes, we show that the heliosheath pressure measured at the poles correlates well with the solar cycle. The analysis requires time-shifting the ENA measurements to account for the travel time out and back from the heliosheath, which allows us to estimate the scale size of the heliosphere in the polar directions. We arrive at an estimated distance to the center of the ENA source region in the north of 220 auand in the southa distance of 190 au. We also find a good correlation between the solar cycle and the ENA energy spectra at the poles. In particular, the ENA flux for the highest IBEX energy channel (4.3 keV) is quite closely correlated with the areas of the polar coronal holes, in both the north and south, consistent with the notion that polar ENAs at this energy originate from pickup ions of the very high speed wind (∼700 km s −1 ) that emanates from polar coronal holes.

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Interstellar hydrogen ionization in the heliosheath

Gruntman

2015

JGR Space Physics

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The expanding solar wind plasma undergoes a shock transition at the interstellar boundary of the solar system and fills the inner heliosheath, the region between the termination shock and the heliopause. The nonequilibrium heliosheath plasma is a main source of energetic neutral atoms that allow remote probing of the heliospheric interface region. Global models of the heliosphere interaction with the interstellar medium often disregard solar photoionization and electron impact ionization of interstellar gas in the heliosheath. When ionization is included, it is commonly treated in a simplified manner and complexity of heliospheric interactions obscures its effect on the properties of the plasma. This work concentrates on physical estimates of ionization and shows that it may lead to significant mass loading of plasma flows in the heliosheath. In turn, mass loading would slow down plasma flows and deplete populations of nonthermal energetic protons. The magnitude of the effect depends on poorly understood and largely unknown energy transfer to electrons at the termination shock and beyond. The presented estimates show that inclusion of ionization is indispensable for global heliospheric modeling and for interpretation of heliosphere imaging in fluxes of energetic neutral atoms.

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Magnetized Jets Driven by the Sun: The Structure of the Heliosphere Revisited

Cited by 129 publications

References 44 publications

Response times of Cassini/INCA > 5.2 keV ENAs and Voyager ions in the heliosheath over the solar cycle

Response times of Cassini/INCA > 5.2 keV ENAs and Voyager ions in the heliosheath over the solar cycle

Tracking the Solar Cycle Through Ibex Observations of Energetic Neutral Atom Flux Variations at the Heliospheric Poles

Interstellar hydrogen ionization in the heliosheath

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