I enA imaging: seeing the invisible

n what follows, we describe the technique and history of energetic neutral atom (enA) imaging of space plasma and present recent results from international collaborations involving enA imaging experiments as well as results from the imAge mission at earth and the cassini mission at Jupiter and saturn. both imAge and cassini carry ApL-built enA cameras. The henA instrument onboard the imAge mission provides global images of the ring current around the earth and reveals the importance of the electrical coupling between the ring current and the ionosphere. The incA instrument onboard cassini returns enA images from the enormous magnetosphere around saturn, giving unprecedented insight into the dynamics of the hot plasma and its interaction with neutral gas. The review ends with a brief description of enA imaging of the heliospheric boundary and future projects using enA instrumentation

Parametric analysis of nightside conductance effects on inner magnetospheric dynamics for the 17 April 2002 storm

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95027/1/jgra17945.pd

Impulsive enhancements of oxygen ions during substorms.

It has been observed that H+ is the dominant ion species in the plasma sheet and the ring current during quiet times. However, the O+/H+ density ratio increases with increasing geomagnetic storm and substorm activity. Energetic neutral atom (ENA) images from Imager for Magnetopause-to-Aurora Global Exploration/High Energy Neutral Atom (IMAGE/HENA) reveal the rapid increase of O+ ring current at substorm expansion. Finding the cause of this substorm-associated O+ enhancement is the main focus of this paper. Two possible sources are suggested: direct injection from the ionosphere and energization of the preexisting oxygen ions in the magnetosphere. We perform numerical simulations to examine these two mechanisms. Millions of O+ are released from the auroral region during a simulated substorm by the Lyon-Fedder-Mobarry MHD model. The subsequent trajectories of these outflowing ions are calculated by solving the full equation of particle motion. A few minutes into the substorm expansion phase, an enhancement in O+ pressure is found on the nightside at ∼12 RE. After careful analysis, we conclude that this pressure peak is coming from energization of the preexisting O+ in the plasma sheet. The direct injection mechanism will introduce a significant time lag between strong ionospheric outflow and magnetospheric enhancement, so that it cannot explain the observed O+ bursts. Using the temperature and density established by the test-particle calculations as boundary conditions to a ring current model, we calculate the O+ fluxes and the corresponding ENA emissions during the model substorm. We are able to reproduce observable features of oxygen ENA enhancements as seen by IMAGE/HENA

Understanding our global heliosphere with UV observations: Unique opportunities on Interstellar Probe

International audienceSolar Lyman-a emission re-radiated from H atoms incoming to the heliosphere from interstellar medium is a powerful tool to probe globally plasma properties both at the heliosphere boundary and near the Sun. H Lyman-α line profiles reflect velocity distributions of low energy H atoms in the heliosphere which hold information about the plasma near the heliopause. H Lyman α intensities as observed at 1 AU serve as diagnostic of global properties of the solar wind. In this talk we will review what we have learned about the global heliospheric interaction from H Lyman-a observations from inside the heliosphere on SWAN/SOHO, Voyages/UVS and New Horizons/Alice missions. Outward trajectory of Interstellar Probe going through the outer heliosphere to the interstellar medium (ISM) up to 1000 AU enable unique science opportunities to explore global interaction between the solar wind and local ISM by observing for the first time Lyman-a emission from outside of the heliosphere. We will report a progress of UV working group in outlining primary science questions on the nature of the global heliosphere and Local Interstellar Cloud, planning observation strategy, measurement requirements and synergies with planetary UV observations for potential KBO fly-by

STELLA – A proposal for Europe’s contribution to a possible Interstellar Probe

International audienceStella is a proposed European contribution to NASA’s Interstellar Probe (ISP), a large-strategic mission candidate. ESA’s call for M-class mission proposals was the best and only currently available option for the European science community to contribute to the astronomically constrained ISP launch window in 2036 – 2037. Traveling with a speed of ~ 7.0 au/year ISP would reach 350 au during its nominal 50-year life-time. The proposed Stella contribution to ISP includes two core and two optional elements for the full complement:• Core: Provision of European scientific instruments;• Core: Provision of the European ISP communication system including the spacecraft’s 5-m high gain antenna;• Full complement: ESA deep space communication facility: an extension of ESA’s DSA with a new antenna array;• Full complement: Contribution to ISP operations to increase drastically the ISP and European payloads science return

STELLA – A proposal for Europe’s contribution to a possible Interstellar Probe

International audienceStella is a proposed European contribution to NASA’s Interstellar Probe (ISP), a large-strategic mission candidate. ESA’s call for M-class mission proposals was the best and only currently available option for the European science community to contribute to the astronomically constrained ISP launch window in 2036 – 2037. Traveling with a speed of ~ 7.0 au/year ISP would reach 350 au during its nominal 50-year life-time. The proposed Stella contribution to ISP includes two core and two optional elements for the full complement:• Core: Provision of European scientific instruments;• Core: Provision of the European ISP communication system including the spacecraft’s 5-m high gain antenna;• Full complement: ESA deep space communication facility: an extension of ESA’s DSA with a new antenna array;• Full complement: Contribution to ISP operations to increase drastically the ISP and European payloads science return

STELLA — In situ Investigations of the Very Local Interstellar Medium. Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033 white paper e-id. 433

International audienceVoyager 1 & 2, Ulysses, Cassini, and IBEX have shown that the interaction between interstellar medium and solar wind is much more complex and involved than previously believed. This whitepaper proposes to study this interaction in situ at the heliospheric boundaries and to explore the very local interstellar medium beyond with new instrumentation that is built to investigate this final frontier

STELLA — In situ Investigations of the Very Local Interstellar Medium. Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033 white paper e-id. 433

International audienceVoyager 1 & 2, Ulysses, Cassini, and IBEX have shown that the interaction between interstellar medium and solar wind is much more complex and involved than previously believed. This whitepaper proposes to study this interaction in situ at the heliospheric boundaries and to explore the very local interstellar medium beyond with new instrumentation that is built to investigate this final frontier