Dust, Field and Plasma instruments onboard Comet Interceptor: new challenges for pristine comet diagnostics.

ESA's Comet Interceptor mission is designed to fly by a dynamically new comet with three individual spacecraft. This offers a unique opportunity for multi-point measurements of the comet's dust, plasma and magnetic field environment, a first in cometary exploration. Most in-situ plasma science sensors therefore, have been tightly integrated into a suit  Dust, Field and Plasma (DFP) instrument on the ESA-led main spacecraft A and sub-spacecraft B2

On spacecraft A, DFP consists of a magnetometer, a Langmuir and mutual impedance probe, an ion and electron analyser, a dust sensor, and a central data processing unit and electronics box. On spacecraft B2, the instrumentation is limited to a magnetometer and a dust sensor, supply system, central data processing and electronic box. The choice of sensors and their capabilities are such that it maximises synergies and complementarities.

The DFP A and B2 suit instruments are dedicated to the in situ, multi-point study of the multi-phased ionized and dusty environment in the coma of the target dynamically new comet and of its interaction with the surrounding space environment and the Sun. The DFP will measure magnetic field, electric field, plasma parameters (density, temperature, speed), the distribution functions of electrons, ions and energetic neutrals, spacecraft potential and the cometary dust, in order to

- identify boundaries and regions in the cometary environment of a comet and its interaction with the Sun and the solar wind (e.g., bow shock, diamagnetic cavity) and to assess their structure;

- map the dust and plasma phases around the target dynamically, new comet;

- assess the mass, momentum and energy transfer in the cometary environment;

- provide simultaneous magnetic field, plasma and dust measurements to identify the interplay between the ionised and dusty phases around a comet and characterise dusty plasma properties;

- map the solar wind – coma interaction;

- describe and map the (i) electron, (ii) negative and positive ion and (iii) energetic neutral atom distribution functions in the vicinity of the comet and in the interaction region with the solar wind;

- Identify the electron and ion kinetic processes that mediate the solar wind-comet interactions from ion kinetic scales, down to electron scales.

This presentation aims to show the possibilities of  plasma environment diagnostics and the current status  of DFP instrument design and construction, and also presents the observation plans  and challenges of multipoint plasma diagnostics