importantly heavy ions 46 will travel on helical paths of relatively large radius causing them to strike the inner surface of the wave guide 16 and be captured on the other hand light ions 44 will travel on helical paths of relatively small radius causing them to transit through the plasma chamber 12 specifically the demarcation between light ions 44 and heavy ions 46 is a cut off mass m c which can be established by the expression in this expression e is the charge on an electron and the other variables have been defined above of these variables in the expression a b z and v ctr can all be specifically designed or established in view of the ions that require separation as indicated above and shown in fig2 the heavy ions 46 strike the inner surface of the wave guide 16 and are captured if desired a collector not shown can be installed in the wave guide 16 to facilitate capture of the heavy ions 46 the light ions 44 on the other hand transit the plasma chamber 12 and exit through end 22 of the wave guide 16 for collection if desired a collector not shown can be installed at the end 22 of the wave guide 16 to facilitate capture of the light ions 44 importantly the light ions 44 and heavy ions 46 are prevented from exiting the plasma chamber 12 through the end 20 of the wave guide 16 due to the ponderomotive forces that are generated.