Solar phenomena move about and can travel at a few hundred meters per second when they first appear. The solar wind is a stream of plasma released from the Sun's upper atmosphere. It consists of mostly electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in density, temperature and speed over time and over solar longitude. These particles can escape the Sun's gravity because of their high energy. The solar wind is divided into the slow solar wind and the fast solar wind. The slow solar wind has a velocity of about , a temperature
AWAKE bunch in the wakefield is thus crucial, since only a fraction (1/4th) of the wakefield is both focused and accelerated, which is needed for the trapping and the acceleration of the electrons. AWAKE is the first plasma wakefield experiment using a bunch of protons as a driver. Protons, as e.g. the protons form the CERN SPS, can carry a large amount of energy (~ 400 GeV). Therefore, they can produce wakefields in a plasma for much longer distances than a laser pulse or electron bunch as a driver due to energy depletion. A plasma can be seen as an ensemble