Transformation of the magnetic energy of a rotating relativistic beam into plasma energy

An intense rotating relativistic electron beam of energy 500 kV and current 40−50 kA is injected into neutral gas of pressure 200−700 mTorr, in the presence of an external magnetic field B0≃800 G. It is observed that the ratio of the magnetic field on axis ΔBz(r=0) to B0 is ΔBz(r=0)/B0≃2.2. The average magnetic energy density is about 2.5×1016 eV cm−3. Spectroscopic results show that most of this energy is transferred to the plasma through Joule heating.