The New Garching Fast ERA Experiment

A single-turn coil for fast electron ring compression and magnetic expansion acceleration was built. It combines a fast magnetic field rise (dBz/dt /injection = 3×109 G/s) for very fast resonance crossing (within less than 100 ns) with a smooth and weak expansion field (Br = 5 G, dBr/dr /spill out < 0.5 G/cm). The first experiments showed strong collective behaviour of the electron ring at particle numbers of Ne = 5 × 1012, mainly radial collective oscillations with the frequency (1 - ¿r) ¿o, which could be suppressed by increasing the corresponding Landau damping coefficient.