A SUBSURFACE FLOW OF MATERIAL FROM THE SUNS EQUATOR TO ITS POLES

Gas an the Sun's surface has been observed(1-4) to flow away from the equator towards both poles. If the same flow persists to great depths, it could plap an important dynamical role in the the eleven-year suns pot cycle, by carrying the magnetic remnants of the sunspots to high l atitudes(5). An even deeper counterflow, which would be required to ma intain mass balance, could explain why new sunspots form at lower lati tudes as the cycle progresses(6). These deep flows would also redistri bute angular momentum within the Sun, and therefore help to maintain t he faster rotation of the equator relative to the poles(7). Here pie r eport the detection, using helioseismic tomography, of the longitude-a veraged subsurface now in the outer 4% of the Sun. We find that the su bsurface now is approximately constant in this depth range, and that t he speed is similar to that seen on the surface. This demonstrates tha t the surface flow penetrates deeply, sep that it is likely to be an i mportant factor In solar dynamics.