5.3 Resolved-Sun measurements

In the meantime, resolved-Sun observations provided some information about the rotation in the radiative interior. Duvall Jr and Harvey (1984Jump To The Next Citation Point) reported observations at Kitt Peak, from 10 – 26 May 1983, for degrees 0 ≤ l ≤ 100. When plotted as a function of degree, the results show a slow decrease in the rotational splitting, from the highest degrees down to about l = 6, with an unexplained bump at l = 11, followed by an increase at lower degrees up to a value of 660 nHz for l = 1. These data, inverted by Duvall Jr et al. (1984Jump To The Next Citation Point), yielded a rotation profile with much of the radiative interior rotating at or below the surface rate, but with a modest increase in the interior. A similar pattern was found by Brown (1985Jump To The Next Citation Point), using 6 days of observations from the newly-developed Fourier Tachometer, a true 2-dimensional imaging instrument that gave access to all the azimuthal orders for degrees between 8 and 50; however, the coincidence of the l = 11 bump seems to have been merely a coincidence of noise, as it was not reproduced in the early observations from the Big Bear Solar Observatory (Libbrecht, 1986Jump To The Next Citation Point).
  Go to previous page Go up Go to next page