Micro- and macroinhomogeneities of density in a quiescent prominence

Abstract

The analysis of a bright prominence of August 13, 1972 was carried out. Continuous spectrum due to Thomson scattering of solar radiation on free electrons and the Balmer precontinuum stipulated by free bounded transitions in the volumes with different electron concentration n_e (Kurochka, Kiryukhina, 1989) were observed in the spectrum of this prominence. Heir intensities can be explained only by assuming that there are volumes with different values of electron concentration ( 10¹⁰ ⩽ n_e ⩽ 10¹² cm⁻³) and extension in the prominence ( 10⁵ ⩽ ℓ ⩽ 10⁹ ).

In addition, there are extended volumes ( with ℓ of the order of the active region size and even larger) with relatively low temperature( T_e < 10⁴ K) and electron concentration intermediate between the concentration in the prominence and that of the corona( 10⁹ ⩽ n_e ⩽ 10¹⁰ cm ⁻³ ).

The problem of existence of micro- and macroinhomogeneities of density in prominence and in the volumes around the prominence originated at bringing to the agrement the observed intensity of the continuous spectrum of the prominence T _scin the region λ 3700 Å with the intensity of Balmer continuum T _c,2 which increased from λ 3685 Å up to λ 3650 Å in the prominence studied.

The spectrum of the prominence was obtained on August 13, 1972 (λ = +90°, f = +12°) under highland conditions (altitude 3000 m) and at high transparency of the earth atmosphere.