LATITUDINAL DISTRIBUTION OF SOLAR-WIND AS DEDUCED FROM LYMAN-ALPHA MEASUREMENTS - AN IMPROVED METHOD

In this work we examine the possibility of deducing the latitudinal di stribution of the solar ionization rate using Prognoz 6 Lyman alpha da ta in a more general and flexible way than previously examined. Using so-called hot model for the hydrogen distribution and the optically th in model for the resonance scattering, theoretical Lyman alpha intensi ty for the interstellar hydrogen is calculated and compared with the i ntensity data measured by Prognoz 6. Varying the latitudinal dependenc e of the ionization rate, the distributions. which produce the best fi t with the data, are analyzed for four different measuring sessions. A s a result, we get four ionization rate distributions that have two co mmon features. The ionization rate is enhanced near the solar equator, and large broad plateaus exist around heliographic latitudes +/-30-de grees to +/-70-degrees. The latitudinal distribution of the average io nization rate about the solar minimum deviates clearly from the spheri cally symmetric and sinusoidally (harmonically) with the latitude-vary ing models used so far. The growth of the solar wind mass flux from th e solar polar areas toward the equator corresponds to the earlier resu lts concluded from Lyman alpha measurements. The method used in this w ork allows a higher latitudinal resolution of the ionization rates. Ho wever, there are several uncertainities both in the simulations and in the measurements. The exclusion of time-dependent effects as well as multiple scattering requires that the results be considered only sugge stive.