18th VEXAG Meeting 2020 (LPI Contrib. No. 2356) 8035.pdf

FUTURE SPACE PHYSICS AT VENUS. G. A. Collinson1, C. Fowler2, R. Ramstad3, S. Curry2, M. Chaffin3, S. Xu2, S. Boucher4, G. DiBraccio1, C. Dong5, Y. Futaana6, M. Fillingin1, R. Jarvinen7, S. Ledvina2, J. Luhmann2, Joe O’Rourke8, Chris Russell9, Moa Persson6, Michael Way10,

1NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA, [email protected] 2University of California, Berkeley, CA, USA 4University of Michigan, Ann Arbor, MI, USA 5Princetown University, NJ, USA, 6IRF Kiruna, Sweden, 7Finnish Meteorological Institute, Helsinki, Finland, 8Arizona State University, AZ, USA, 9 University of California, Los Angeles, CA, USA, 10Goddard Institute for Space Studies, NY, USA

We summarize white papers recently submitted to the producing an induced magnetosphere that acts to slow Planetary Science and Astrobiology Decadal Survey down and deflect the solar wind around Venus. This 2023-2032. interaction leads to a highly structured and dynamic plasma environment that responds strongly to changes EXPLORING ATMOSPHERIC DYNAMICS, ESCAPE, AND in the solar EUV flux and the upstream solar wind EVOLUTION conditions. Our understanding of ancient Venus and its evolution to the present day could be substantially advanced Previous in-situ observations of the Venus plasma through future Space Physics investigations from orbit. environment have provided information on the basic We outline three high-priority strawman physical processes that dictate this interaction, investigations, each possible for relative thrift with however, limitations in instrument capabilities, solar existing (or near-future) technology. 1.) To understand cycle phase, and orbit coverage have left a plethora of the physical processes that facilitate Venusian questions unanswered. In particular, comprehensive atmospheric escape to space, so that we may (high time cadence and full distribution) plasma, extrapolate backwards through time; 2.) To explore neutral, magnetic and electric and field measurements, ancient Venus through the measurement of the escape as well as simultaneous upstream solar wind monitors, rates of key species such as Deuterium, Noble are needed to fully characterize the state of Venus' elements, and Nitrogen; 3.) To understand and quantify magnetosphere, ionosphere and atmosphere, and the how energy and momentum is transferred from the real-time response of these to variations in upstream solar wind, through the ionosphere, and into the solar wind conditions. atmosphere, so that we may reveal its impact to the dynamics of the atmosphere.

Unravelling the drivers of Venusian ionospheric structure, energy balance and evolution, through in-situ plasma measurements at Venus

We recommend a multi-spacecraft dedicated plasma mission at Venus, capable of sampling the entire induced magnetosphere, while simultaneously measuring the upstream solar extreme ultraviolet (EUV) flux and solar wind. Such observations, obtained over a range of solar activity levels, would revolutionize our understanding of how the Venus time-dependent induced magnetosphere and ionosphere respond to solar EUV flux and solar wind variability, and would address several high priority VEXAG and planetary science goals.

The lack of a dipole magnetic field at Venus means that the solar wind interacts directly with the gravitationally bound conducting ionosphere,