Plasma Fusion at 10 MK With Extremely Heated Ions

A new mechanism for plasma fusion at 10 million degree kelvin (MK) with extremely heated (100 MK or hotter) ³He ions was developed. This new mechanism involves a two-stage heating process when an electric current is driven through a multiion plasma with ³He ions. To realize thermonuclear fusion, plasmas must be heated to 100 MK and higher. The ohmic heating process is the simplest, which enables an electric current to heat plasma up to 10 MK. Values above this upper limit the resistivity in the plasma is too low for the electric current to significantly dissipate. The author´s previously well-developed theory for solar ³He-rich events has indicated that current-driven electrostatic H (or proton) cyclotron waves can be easily excited at frequency levels approximately twice the ³He-cyclotron frequency, thus very efficient in heating ³He via the second harmonic resonance. The ³He temperature can be increased by a factor of 10-100 within only hundreds of the H gyro-period. This preferential heating of ³He can be applied as the second-stage heating of an ohmically preheated laboratory or tokamak plasma for fusion with ³He. As the electric current is driven through, the plasma is gradually heated up to 10 MK due to the ohmic dissipation and saturates at this level of temperature because of low loss rate. When the electric current is continuously driven up to a critical point, the electrostatic H-cyclotron waves are excited, which can further heat ³He to 100 MK and higher, at which the nuclear fusion between the extremely hot ³He and the other relative cold deuterium (D) ions can occur. In a tokamak (e.g., ITER), if the plasma is composed of e, H, D, and ³He with abundances n_H>n_D >>n(³He) and when ³He is preferentially heated to 100 MK and higher by the current-driven electrostatic H-cyclotron wav- s, the plasma dominant species of ions (H and D) are still around 10 MK. This new mechanism for plasma fusion at 10 MK with extremely heated ³He ions can also greatly reduce the difficulty in controlling and confining the plasma as well as avoid any explosions of the fusion device when extremely hot ³He ions fuse with relative cold D ions.