Excitation of Chromospheric he I.

New calculations are carried out for bj for the singlet and triplet states of He 1, using corrected transition rates from our earlier analysis (Athay and Johnson 1960). The new results differ considerably from our earlier calculations and lead to a new chromospheric model, whose major changes are in the geometry of the helium regions. Chromospheric emission observed at the limb at heights above 1000 km is largely confined to spicules with electron densities, ,i , of the order of . Helium regions are identified as hot shells, having electron temperatures, T 5 X 10 , incasing colder spicule cores. Interspicule regions must have n <= 3 X 1010 and T >= 3 X 10 . This new model is consistent with radio data at millimeter wavelengths and is similar to that proposed by Moriyama (1961).