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The recently published Interstellar Probe (ISP) study report describes a pragmatic mission concept with a launch window that starts in 2036 and is expected to reach several hundreds of astronomical units past the heliopause within a time frame of ≥50 years (https://interstellarprobe.jhuapl.edu/Interstellar-Probe-MCR.pdf). Following the ISP report, this paper, that will also be accessible from the Bulletin of the AAS (BAAS) in the framework of the Decadal Survey for Solar and Space Physics (Heliophysics) 2024–2033 (Dialynas et al., A future Interstellar Probe on the dynamic heliosphere and its interaction with the very local interstellar medium: In-situ particle and fields measurements and remotely sensed ENAs, 2022a), aims to highlight the importance of studying the physics of the interactions pertaining to the expanding solar wind that meets the plasma, gas and dust flows of the very local interstellar medium, forming the complex and vast region of our astrosphere. We focus on three fundamental open science questions that reveal the dynamical nature of the heliosphere A) Where are the heliosphere boundaries and how thick is the heliosheath B) Is there a “missing” pressure component towards exploring the dynamics of the global heliosheath and its interaction with the very local interstellar medium C) Why does the shape and size of the global heliosphere appear different in different Energetic Neutral Atom energies? We argue that these questions can only be addressed by exploiting a combination of in-situ charged particle, plasma waves and fields measurements with remotely sensed Energetic Neutral Atoms that can be measured simultaneously from the instruments of a future Interstellar Probe mission, along its trajectory from interplanetary space through the heliosheath and out to the very local interstellar medium., Frontiers in Astronomy and Space Sciences, 10, ISSN:2296-987X

Voyager 2 observations throughout the heliosheath from the termination shock to the heliopause are used to normalize and constrain model pickup ion (PUI) fluxes. Integrating normalized PUI fluxes along the Voyager 2 trajectory through the heliosheath, and combining these integral fluxes with the energy-dependent charge-exchange cross section and the neutral hydrogen density, produces semi-empirical estimates of the energetic neutral atom (ENA) fluxes from the heliosheath. These estimated ENA fluxes are compared with observed ENA fluxes from the Interstellar Boundary Explorer (IBEX) to determine what percentage of the observed fluxes at each IBEX energy are from the heliosheath. These percentages are a maximum of ∼10% for most energies and depend strongly on termination shock properties, plasma density, bulk plasma flow characteristics, the shape of the heliopause, and turbulent energy diffusion in the heliosheath.

We show that the neutral gas vertical distribution at Saturn must be ~3-4 times more extended than previously thought for the >5 RSregions, while the neutral H distribution is consistent with H densities that reach up to ~150/cm3close to the orbit of Titan. We utilize a technique to retrieve the global neutral gas distribution in Saturn's magnetosphere, using energetic ion and energetic neutral atom (ENA) measurements, obtained by the Magnetospheric Imaging Instrument (MIMI) onboard the Cassini spacecraft. Our ENA measurements are consistent with a neutral cloud that consists of H 2O, OH, H, and O, while the overall shapes and densities numbers concerning the neutral gas distributions are constrained according to already existing models as well as recent observations. The neutral gas distribution at Saturn is determined by simulating a 24-55 keV hydrogen image of the Saturnian magnetosphere, measured by the Ion and Neutral Camera (INCA), averaged over the time period from 1 July 2004 to 23 August 2005. The ionic input of the model includes a proton distribution of combined Charge Energy Mass Spectrometer (CHEMS, 3-230 keV/e), Low Energy Magnetospheric Measurements System (LEMMS, 30.7 keV to 2.3 MeV), and INCA (5-300 keV) in situ measurements. These measurements cover several passes from 1 July 2004 to 10 April 2007, at various local times over the dipole L range 5< L

We report observations of Titans high-altitude exosphere detected out to about 50,000 km altitude. The observations were made by the Ion Neutral Camera (INCA) on board the Cassini spacecraft. INCA detects energetic neutral atoms (ENA) that are formed when the ambient magnetospheric ions charge exchange with Titans neutral atmosphere and exosphere. We find that Titans exospheric H 2 distribution follows closely a full Chamberlain distribution including ballistic, escaping and satellite distributions. As expected, neutral densities are dominated by a satellite distribution above about 10,000 km. The maximum detectable extent of the exosphere (∼50,000 km) coincides with the radius of the Hill sphere of gravitational influence from Saturn. While we find no direct indications of a neutral Titan torus with densities greater than about 1000 cm -3, we observe interesting asymmetries in the distribution that warrants further investigation. Based on these findings we compute the average precipitating ENA flux to be about 5×10 6 keV/(cm 2 s), or 8×10 -3 erg/(cm 2 s), which is directly comparable to that of precipitating energetic ions (Sittler, et al, 2009) and slightly higher than that of solar EUV (Tobiska, 2004). Thus, the energy deposited by precipitating ENAs must also be taken into consideration when studying the energy balance of Titans thermosphere. © 2011 Elsevier Ltd. All rights reserved.

We characterize the relative importance of energetic electrons and protons to the weathering of five of the inner satellites of Saturn. To do this, we present data from the Magnetospheric Imaging Instrument on the Cassini spacecraft, some of which is averaged over the whole mission to date. We also compute averaged proton and electron energy spectra relevant to the distances of these inner satellites. Where data are available, we estimate the power per unit area into a satellites surface. For electron energy deposition into satellite leading hemispheres, we find the power per unit area is greatest at Mimas and falls off with distance from Saturn. Using fluxes of 150 MeV protons detected within the sweeping corridors of Mimas and Enceladus, we find the corresponding deposition would be about 2×10 8 and 3.7×10 7 eV/cm 2 s. © 2011 Elsevier Ltd. All rights reserved.

We present unique observations obtained by the Magnetospheric Imaging Instrument (MIMI) on the Cassini spacecraft, of the Kronian magnetosphere during the approach phase and subsequent several orbits of the Cassini spacecraft around the planet. High sensitivity observations of energetic ion directional intensities, energy spectra, and ion composition were obtained by the Ion and Neural Cameral (INCA) of the MIMI instrument complement with a geometry factor of similar to 2.5 cm(2) sr. Charge state information was provided by the Charge-Energy-Mass-Spectrometer (CHEMS) over the range similar to 3 to 220 keV per charge. The observations revealed the presence of distinct upstream bursts of energetic hydrogen and oxygen ions up to distances of similar to 135Rs. The observations are presented and their theoretical implications are addressed.

We report sample results on Saturn magnetospheric energetic ion spectral shapes using measurements obtained from the Magnetospheric Imaging Instrument (MIMI) suite onboard Cassini. The ion intensities are measured by the Charge Energy Mass Spectrometer (CHEMS) that covers the energy range of 3 to 236 keV/e, the Low Energy Magnetospheric Measurements System (LEMMS) covering the energy range of 0.024 < E < 18 MeV, and the Ion Neutral Camera (INCA) that provides ion measurements in the ion mode at the energy range ∼5.5 to >220 keV for protons. The data used cover several passes from the period 1 July 2004 to 10 April 2007, at various latitudes over the dipole L range 5 < L < 20 RS. The spectra generally show a power law in energy form at larger L values but display a flattening/relative peak at lower (L < 10) values centered at ∼50 to ∼100 keV and can be fit by a κ distribution function with characteristic kT ranging from ∼10 to ∼100 keV. The results are consistent with the assumption that energetic protons are heated adiabatically as they move inward to stronger magnetic fields, in contrast to the singly ionized oxygen that seems to be heated locally at each L shell. The lack of any trend of the O+ temperature versus L shell implies that nonadiabatic energization mechanisms and charge exchange with Saturn's neutral gas cloud play an important role for ion energetics. Copyright 2009 by the American Geophysical Union.

Radiation belts have been detected in situ at five planets. Only at Earth however has any variability in their intensity been heretofore observed, in indirect response to solar eruptions and high altitude nuclear explosions. The Cassini spacecraft's MIMI/LEMMS instrument has now detected systematic radiation belt variability elsewhere. We report three sudden increases in energetic ion intensity around Saturn, in the vicinity of the moons Dione and Tethys, each lasting for several weeks, in response to interplanetary events caused by solar eruptions. However, the intensifications, which could create temporary satellite atmospheres at the aforementioned moons, were sharply restricted outside the orbit of Tethys. Unlike Earth, Saturn has almost unchanging inner ion radiation belts: due to Saturn's near-symmetrical magnetic field, Tethys and Dione inhibit inward radial transport of energetic ions, shielding the planet's main, inner radiation belt from solar wind influences. Copyright 2008 by the American Geophysical Union.