1. Solar system science using X-Rays Magnetosheath dynamics Shock – shock interactions Auroral X-ray emissions Solar X-rays Comets Other planets Not discussed here

2. Background Solar wind interacts with the Earth’s magnetic field to create the earth’s magnetosphere Specifically solar wind is slowed from super-sonic (Alfvenic) by the presence of the earth Creates the BOW SHOCK up front of the Earth – a collisionless shock Between the bow shock and outer boundary of earth’s magnetic field is the MAGNETOSHEATH This is a region of shocked, slowed, turbulent plasma and is one key region where X-ray observations may be made

3. Magnetospheric Dynamics Position of bow shock and magnetopause are controlled by two main factors – solar wind dynamic pressure and orientation of interplanetary magnetic field Solar wind dynamic pressure controls the large scale position and variations in pressure determine the large scale dynamics Orientation of the IMF leads to magnetospheric dynamics through magnetic reconnection at the magnetopause Timescales for both these processes can be short (few seconds to minutes) Spatial scales can be very different – reconnection relatively small scale while dynamic pressure variatiosn affect the whole system

4. What can we learn? Current knowledge is based on in situ spacecraft measurements – mainly individual s/c but now Cluster Even Cluster only provides small scale information about bow shock and magnetopause dynamics Large scale structure from simple empirical models based on solar wind pressure Large scale dynamics are unknown

5. What can we learn? Numerical simulation of X-ray intensity in sheath and magnetic cusps (top) Numerical simulation shows how the region may change under extreme solar wind conditions (left Panel) compared with average conditions (right panel) Note that the colour scale is different for the two conditions Solar wind contains interplanetary shocks caused by motion of fast solar wind through the slow/average solar wind Provides opportunity to study shock-shock interactions on a large scale

6. What can we learn? Numerical simulation of X-ray intensity in sheath and magnetic cusps (top) Numerical simulation shows how the region may change under extreme solar wind conditions (left Panel) compared with average conditions (right panel) Note that the colour scale is different for the two conditions Solar wind contains interplanetary shocks caused by motion of fast solar wind through the slow/average solar wind Provides opportunity to study shock-shock interactions on a large scale

7. X-ray Aurora Few observations of auroral activity from space PIXIE on Polar is the only mission to my knowledge with long timeframe Poor temporal and spatial resolution compared with visible and UV observations from same platform Potential for Lunar mission to provide images at X-rays X-rays provide information on spatial distribution of the higher energy particle precipitation

8. Issues that need resolving Spatial resolution from lunar orbit Temporal resolution from lunar orbit Can spectral information be used to provide high charge state heavy ion mass densities? Provides information on region of origin of solar wind. Others…..