Physics of AWAKE Run 2

This document describes the gain in our knowledge of plasma wakefield physics as well as gives a first glimpse of the particle physics possibilities that will be made possible given the successful completion of the AWAKE experimental program. The knowledge gain is here broadly defined in two categories: the gain for particle physics via the slew of new experimental programs made possible by a successful demonstration of proton-driven plasma wakefield acceleration (PDPWA), and the plasma and accelerator physics knowledge that will be acquired from carrying out the AWAKE Run 2 experimental program. We describe both of these aspects in this document.