Observation of radially propagating collisionless-drift-wave instability

The radially traveling drift-wave instability is observed in a fully ionized collisionless plasma. The observed radial wave number is larger than the azimuthal wave number. The observed frequency, in the frame of ErBz plasma rotation, is in good agreement with the calculated frequency of the drift instability after the correction of finite ion inertia including the radial wave number, where Er is a radial electric field and Bz is an axial magnetic field.