Plasma Science and Plasma Instrumentation for an Outer Heliosphere and Interstellar Mission

Abstract:

The Local Interstellar Medium (ISM), including its “very local” component, the VLISM, is a complex mix of interacting components: neutral gas, plasma, galactic cosmic rays and dust particles, interacting with stellar radiations and the local galactic magnetic field. We present a short overview of the mediating role played by plasma populations and charged particles in this complex medium and of their expected dynamics and state of turbulence. We derive from this analysis some guiding requirements for the measurement of thermal ions and electrons in the LISM. By confronting them with the corresponding requirements applying to the measurement of the solar wind (including pick-up ions) in the outer heliosphere, we derive the main characteristics of an instrument we propose to fly on future missions to heliospheric boundaries and to the VLISM. The design of such an instrument will accommodate the low resources and large range of count rates expected over the course of such missions.