VORTEX MUTUAL FRICTION IN ROTATING SUPERFLUID HE-3

The Manchester rotating cryostat has been used to measure the longitud inal and transverse coefficients of vortex mutual friction in tile A a nd B phases of superfluid He-3. In the B phase the dominant contributi on to the mutual friction is scattering of ex-citations off occupied b ound states in tile vortex core. The A phase results are explained qua ntitatively by assuming that doubly quantised continuous vortices are created with a dynamics determined by the equation of motion of the or bital vector 1; the measurements enable us to put an upper limit on th e orbital inertia of less than 0.01HBAR per Cooper pair. History-depen dent textural effects which had to be overcome in order to make meanin gful measurements in the A phase are explained by noting that for a gi ven rotation direction the most stable vortices can be formed more eas ily from one direction of uniform 1 texture than the other.