Emission of energetic neutral atoms from water ice under Ganymede surface-like conditions

Brightness asymmetries on the surface of Ganymede are thought to be caused by ion impact from Jovian co-rotating plasma. The Jovian Neutrals Analyzer instrument onboard the JUICE spacecraft will help investigate this theory by yielding a map of ion precipitation at the surface of Ganymede through the observation of low-energy Energetic Neutral Atoms (ENAs) (10 eV to 3300 eV) sputtered or backscattered by the Jovian plasma. In order to optimize JNA operations planning at Ganymede, we estimate the expected energy distribution of ENAs caused by the impacting Jovian plasma. As an input, we use results from a three dimensional hybrid plasma simulation, which gives us the energy distribution of precipitating H+, O++ and S+++ at the surface of Ganymede. We then calculate the ENA yield using respectively Fam&#224;&#8217;s model (Fam&#224;, 2008) for the sputtering yield of water ice and Thompson-Sigmund&#8217;s model (Sigmund, 1969) for electronic sputtering to get the energy distribution of the ENAs.

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Energetic neutral atoms at Mars 2. Imaging of the solar wind-Phobos interaction

Journal of Geophysical Research Atmospheres ◽

10.1029/2001ja000328 ◽

2002 ◽

Vol 107 (A10) ◽

Cited By ~ 17

Author(s):

Alessandro Mura

Keyword(s):

Solar Wind ◽

Neutral Atoms ◽

Energetic Neutral Atoms

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What Does Our Heliosphere Look Like in Energetic Neutral Atoms? Some Recommendations for a Low-Energy ENA Camera Onboard the Interstellar Probe

10.1002/essoar.10500565.1 ◽

2019 ◽

Author(s):

André Galli ◽

Peter Wurz ◽

Jens Kleimann ◽

Horst Fichtner ◽

Yoshifumi Futaana ◽

...

Keyword(s):

Low Energy ◽

Neutral Atoms ◽

Energetic Neutral Atoms ◽

Interstellar Probe

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Imaging Saturns dust rings using energetic neutral atoms

Planetary and Space Science ◽

10.1016/s0032-0633(97)00201-8 ◽

1998 ◽

Vol 46 (9-10) ◽

pp. 1349-1362 ◽

Cited By ~ 6

Author(s):

B.H. Mauk ◽

S.M. Krimigis ◽

D.G. Mitchell ◽

E.C. Roelof ◽

E.P. Keath ◽

...

Keyword(s):

Neutral Atoms ◽

Energetic Neutral Atoms

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Modeling energetic neutral atoms and the IBEX spectrum

10.1063/1.4723611 ◽

2012 ◽

Author(s):

Jacob Heerikhuisen ◽

Nikolai Pogorelov ◽

Gary Zank

Keyword(s):

Neutral Atoms ◽

Energetic Neutral Atoms

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Structure of the heliosheath from HSTOF energetic neutral atoms measurements

Astronomy and Astrophysics ◽

10.1051/0004-6361/201732432 ◽

2018 ◽

Vol 618 ◽

pp. A26 ◽

Cited By ~ 2

Author(s):

A. Czechowski ◽

M. Hilchenbach ◽

K. C. Hsieh ◽

M. Bzowski ◽

S. Grzedzielski ◽

...

Keyword(s):

Energy Range ◽

Ecliptic Plane ◽

High Energy ◽

Neutral Atoms ◽

Ion Distribution ◽

Ion Density ◽

Heliospheric Observatory ◽

Energetic Neutral Atoms ◽

Time Periods ◽

Ecliptic Longitude

Context. From the year 1996 until now, High energy Suprathermal Time Of Flight sensor (HSTOF) on board Solar and Heliospheric Observatory (SOHO) has been measuring the heliospheric energetic neutral atoms (ENA) flux between ±17° from the ecliptic plane. At present it is the only ENA instrument with the energy range within that of Voyager LECP energetic ion measurements. The energetic ion density and thickness of the inner heliosheath along the Voyager 1 trajectory are now known, and the ENA flux in the HSTOF energy range coming from the Voyager 1 direction may be estimated. Aims. We use HSTOF ENA data and Voyager 1 energetic ion spectrum to compare the regions of the heliosheath observed by HSTOF and Voyager 1. Methods. We compared the HSTOF ENA flux data from the forward and flank sectors of the heliosphere observed in various time periods between the years 1996 and 2010 and calculated the predicted ENA flux from the Voyager 1 direction using the Voyager 1 LECP energetic ion spectrum and including the contributions of charge exchange with both neutral H and He atoms. Results. The ratio between the HSTOF ENA flux from the ecliptic longitude sector 210−300° (the LISM apex sector) for the period 1996−1997 to the estimated ENA flux from the Voyager 1 direction is ∼1.3, but decreases to ∼0.6 for the period 1996−2005 and ∼0.3 for 1998−2006. For the flank longitude sectors (120−210° and 300−30°), the ratio also tends to decrease with time from ∼0.6 for 1996−2005 to ∼0.2 for 2008−2010. We discuss implications of these results for the energetic ion distribution in the heliosheath and the structure of the heliosphere.

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