The precipitation of energetic heavy ions into the upper atmosphere of Jupiter

Horányi, M.; Cravens, T. E.; Waite, J. H.

doi:10.1029/ja093ia07p07251

Cited by 79 publications

(62 citation statements)

References 43 publications

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“…ROSAT observations in the early 1990s confirmed this general picture (Waite et al 1994). Horanyi et al (1988) initially modeled the auroral X-ray emissions in terms of precipitating low (q < 4) charge state O and S ions. subsequently invoked charge exchange with highly charged O ions.…”

Section: Planetary Emissionsmentioning

confidence: 99%

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

et al. 2018

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Both heliophysics and planetary physics seek to understand the complex nature of the solar wind's interaction with solar system obstacles like Earth's magnetosphere, the ionospheres of Venus and Mars, and comets. Studies with this objective are frequently conducted with the help of single or multipoint in situ electromagnetic field and particle observations, guided by the predictions of both local and global numerical simulations, and placed in con- text by observations from far and extreme ultraviolet (FUV, EUV), hard X-ray, and energetic neutral atom imagers (ENA). Each proposed interaction mechanism (e.g., steady or transient magnetic reconnection, local or global magnetic reconnection, ion pick-up, or the KelvinHelmholtz instability) generates diagnostic plasma density structures. The significance of each mechanism to the overall interaction (as measured in terms of atmospheric/ionospheric loss at comets, Venus, and Mars or global magnetospheric/ionospheric convection at Earth) remains to be determined but can be evaluated on the basis of how often the density signatures that it generates are observed as a function of solar wind conditions. This paper reviews efforts to image the diagnostic plasma density structures in the soft (low energy, 0.1-2.0 keV) X-rays produced when high charge state solar wind ions exchange electrons with the exospheric neutrals surrounding solar system obstacles. The introduction notes that theory, local, and global simulations predict the characteristics of plasma boundaries such the bow shock and magnetopause (including location, density gradient, and motion) and regions such as the magnetosheath (including density and width) as a function of location, solar wind conditions, and the particular mechanism operating. In situ measurements confirm the existence of time-and spatial-dependent plasma density structures like the bow shock, magnetosheath, and magnetopause/ionopause at Venus, Mars, comets, and the Earth. However, in situ measurements rarely suffice to determine the global extent of these density structures or their global variation as a function of solar wind conditions, except in the form of empirical studies based on observations from many different times and solar wind conditions. Remote sensing observations provide global information about auroral ovals (FUV and hard X-ray), the terrestrial plasmasphere (EUV), and the terrestrial ring current (ENA). ENA instruments with low energy thresholds (∼ 1 keV) have recently been used to obtain important information concerning the magnetosheaths of Venus, Mars, and the Earth. Recent technological developments make these magnetosheaths valuable potential targets for high-cadence wide-field-of-view soft X-ray imagers.Section 2 describes proposed dayside interaction mechanisms, including reconnection, the Kelvin-Helmholtz instability, and other processes in greater detail with an emphasis on the plasma density structures that they generate. It focuses upon the questions that remain as yet unanswered, such as the significanc...

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Section: Planetary Emissionsmentioning

confidence: 99%

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

et al. 2018

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“…The combined spacecraft measurements indicate an ion energy range of a few keV/u to a few MeV/u. The Voyager results led Horanyi et al [5] to suggest that the auroral x-ray emission was powered by the precipitating ions, the emission being due to radiative decay from highly excited high-charge state 0 and S ions produced following charge exchange with neutral atmospheric species, primarily H2. Horanyi et al [5], and more recently Cravens et al [6], have constructed numerical models of the ion precipitation including energy deposition, beam ionization balance, and auroral x-ray emission.…”

Section: Jovian Atmospheresmentioning

confidence: 99%

“…In what follows we describe the atomic data utilized by the Jovian models [5,6], new data or that not presently considered in the Jovian models, and reactions for which data is lacking. determine the equilibrium ionization fractions of the precipitating ions [6].…”

Section: Jovian Atmospheresmentioning

confidence: 99%

Heavy particle atomic collisions in astrophysics: Beyond H and He targets

Stancil¹,

Krstic²,

Schultz³

1998

Atomic Processes in Plasmas

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Abstract. The physical conditions relatini to the emission of x-rays from Jovi Rec El v E 0 HAY I 4 ' 1998 QWd and cometary atmospheres and to supernova ejecta are briefly described. Emphasis is placed on elucidating the relevance and importance of atomic collision processes, the availability of data, and the outstanding data needs for modeling these environments. Some preliminary theoretical studies of electron capture for important collisions systems, involving molecular and atomic metal targets, are presented.

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“…The discovery of intense X ray emission from Jovian auroras [Metzget et al, 1983;Waite et al, 1994] and measurements of energetic oxygen and sulfur ions [Gehrels and Stone, 1983] and recent observations of X ray and extreme ultraviolet (EUV) emission from comets [Lisse et al, 1996] have stimulated studies of the radiation emitted by highly stripped ions [ Horanyi et al, 1988 0148-0227 / 98 / 98J A-02395 $09.00 charge, E is the energy, and t is the time measured from the time t -0 at which the ion enters the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

“…A significant simplification in the calculation of the energy and charge distribution is achieved by adopting the approximation of an equilibrium charge distribution (ECD) [Horanyi et al, 1988;Cravens et al, 1995].…”

Section: Introductionmentioning

confidence: 99%

X ray and EUV emission spectra of oxygen ions precipitating into the Jovian atmosphere

Kharchenko¹,

Liu²,

Dalgarno³

1998

J. Geophys. Res.

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Abstract. Spectra of soft X ray and EUV emissions of oxygen ions, precipitating into the Jovian atmosphere, are calculated, taking into account the dynamical evolution of the energy and charge distributions of the ions as they propagate. Monte Carlo simulations are performed using experimental and theoretical cross sections of ion collisions with the atmospheric gases. The numbers of X ray and EUV photons produced per precipitating oxygen ion are calculated as functions of the initial ion energy and charge. The energy and charge distribution functions are used to evaluate the intensities of characteristic X ray and EUV emission lines of oxygen ions in Jovian auroras. Radiative cascade transitions from highly excited ion states are shown to be an important source mechanism of soft X ray and ultraviolet emission lines.

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The precipitation of energetic heavy ions into the upper atmosphere of Jupiter

Cited by 79 publications

References 43 publications

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

Heavy particle atomic collisions in astrophysics: Beyond H and He targets

X ray and EUV emission spectra of oxygen ions precipitating into the Jovian atmosphere

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