Electron equilibrium and confinement in a modified Penning trap and its application to Penning fusion

The Penning fusion concept is described. Recent theoretical work on elimina ting limitations on thermonuclear gain (Q) associated with ion-ion collisio ns is reviewed. A critical issue identified is the demonstration of the des ired spherical electron configuration. Constraints on the electron distribu tion function are derived. A small combined trap (majority electrons), PFX- I (Penning Fusion eXperiment-Ions) has been constructed to study these issu es. PFX-I is described. Two diagnostics described for electrons are destruc tive dumping of trapped electrons and noninvasive optical detection of impa ct induced fluorescence. Initial results of PFX-I operation at applied volt ages V-0 up to 2 kV and magnetic fields B up to 1.14 T are described. Elect ron equilibrium is found to be consistent with trap filling to the space ch arge limit, with inventory proportional to V-0 and independent of B. Electr on confinement times range from 1 to 10 ms and are determined by neutral pr essure. These results are interpreted and future directions sketched. (C) 2 000 American Institute of Physics. [S1070-664X(00)93505-5].