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
Plasma acceleration with PWFA, was reported by a research group at Argonne National Laboratory in 1988. The acceleration gradient for a linear plasma wave is: In this equation, formula_2 is the electric field, formula_3 is the speed of light in vacuum, formula_4 is the mass of the electron, formula_5 is the plasma electron density (in particles per metre cubed), and formula_6 is the permittivity of free space. Currently, plasma-based particle accelerators are in the proof of concept phase at the following institutions: Plasma acceleration Plasma acceleration is a technique for accelerating charged particles, such as electrons, positrons, and ions, using the electric