If an ample amount is released, such cells offer an attractive small power source for future distributed energy systems. The IEC concept requires maintaining a beam-like ion distribution to provide high fusion energy gains. However, ion-ion collisions tend to drive the system to thermal equilibrium, thus degrading the ion beams. The principle of the traveling wave direct energy converter mechanism is understood as a combination of a traveling wave tube and a linear accelerator. 3-D numerical simulations are being carried out to optimize device parameters.
Recycling is the process by which particles are returned to a plasma.
Recycling in magnetic fusion devices is dominated by the surfaces in contact with the plasma-walls, limiters, and divertor plates. To understand and possibly control recycling it is necessary to know the ion and neutral atom energy and particle emission coefficients for a variety of materials at the energy of the incident particles, 1-1000 eV. New models that include sputtering, reflection, and the transport particularly of hydrocarbons in the plasma are being developed and applied to current fusion research devices. One region of particular concern is the edge region where the plasma strikes the wall. The helium produced by the fusion events needs to be exhausted, and the power load must not melt the wall and contaminate the plasma. Complete modeling of this edge region, including the detailed macroscopic and microscopic geometry and neutral atom scattering, is of critical importance.