One of the aims of ITER is to reach ignition, when the alpha particles generated by the D-T reaction are able to keep the plasma hot. To get to this point, however, immense power has to be injected to raise the temperature to the order of 50 keV (500,000,000°). This is done mainly with NBI. ITER will have 33 MW of NBI. The injectors, three or four of them, are usually the largest appendages sticking out of the tokamak. In the first stage, deuterium atoms are given an extra electron to produce negative ions. Once charged, the ions can be accelerated electrostatically. Before entering the tokamak, the negative ions go through a little gas, which strips off the extra electron, restoring the atom to a neutral state. Being neutral, the atom is not affected by the magnetic field and can go well into the plasma until it is ionized by the electrons in the plasma. How far it goes depends on its energy. All large tokamaks use NBI, which is a well-established technology; but since ITER is so large, neutral beams of 1 MeV energy are needed to get to the center. NBI technology for 1 MeV has not yet been developed [15].