Performance and preliminary results of the AWAKE experiment in the 2021 proton run

In Run 1 (2016-2018), the AWAKE experiment demonstrated that it was possible to accelerate externally-injected electrons to 2 GeV in plasma wakefields driven by a self-modulated proton bunch. In Run 2 (2021-2028+), AWAKE aims to improve even further the accelerating gradient in the plasma, as well as to demonstrate the scalability of the acceleration process and the beam quality and reliability of the accelerated electrons, in order to demonstrate that it is ready for particle physics applications. During the proton run starting in July 2021--Run 2a--we will study several key ingredients of the Run 2 program: (i) the event-to-event phase reproducible self-modulation of the entire proton bunch seeded by a short electron bunch preceding the protons, (ii) the effect of a phase difference between the front and the back of a proton bunch, (iii) the hosing instability at long wavelengths, and (iv) new diagnostics to measure the intensity of plasma wakefields. The performance of the laser, electron and proton beams in the AWAKE experiment, including their diagnostics and data acquisition systems, will be discussed, and preliminary results of the 2021 run will be presented.