Dynamics of H? spicules according to spectral observations at various heights of the solar chromosphere

Abstract

Almost simultaneous height sequences of 69 spicules in the Ha line have been studied. The spectra are obtained at six heights during 6 s on the east side of the solar disk with the 53-cm Lyot coronagraph of Abastumani Astrophysical Observatory.Radial velocities V,, total intensities or equivalent widths W, full widths at half maximum of intensity (FWHM) at all heights are determined (about 300 profiles of the Ha line). It is found that:(1) Absolute values of radial velocities increase linearly with the height (see Equation (1));(2) variation of the sign of the radial velocity along single spicules was never observed. These results combined with the findings on the spicules radial velocities and shifts obtained earlier (Kulidzanishvili and Nikolsky, 1978;Nikolsky and Platova, 1970) led us to the conclusion that the 5-rain tangential oscillations of spicules involve the entire spicule at once.The intensity height scales for single spicules and for the chromosphere 'in toto' are determined; they turned out to be 2.5 x 10 a km and 1.9 • 103 km respectively (see Equations (2) and (3)).The dependence curve of the Ha line half-widths AA on the height h is drawn. The Ha line half-width for those spicule groups which are traced at all heights (10 spicules) decreases with the height (Figure 4); for the majority (-60 spicules) it remains essentially constant. Non-thermal 'turbulent' velocities Vt in Ha spicules are defined. A mean value of the 'turbulent' velocity Vt at T = 6000 ~ appeared to be 20-30 km s -1.The hydrogen concentration in the spicules at 5000 km is 6 • 1011 cm -3.

Solar Fine-Scale Structures. I. Spicules and Other Small-Scale, Jet-Like Events at the Chromospheric Level: Observations and Physical Parameters

“…The main reason for these discrepancies are due to the fact that observations of spicules at various heights simultaneously are related to instrumental difficulties. Kulidzanishvili (1980) studied almost simultaneously height sequences of 69 spicules in the Hα line. He claimed that absolute values of LOS velocities increase linearly with height and that no variation of the sign of the LOS velocity along individual spicules is observed.…”

Spectroscopic Studies of Limb Spicules. I. Radial and Turbulent Velocities

“…As for the fast components, we assume that their surrounding magnetic field is nearly parallel to the LOS, so the Alfvén waves will not contribute to line-broadening, agreeing with their narrow widths even if they are composed of multiple finer threads. Kulidzanishvili (1980) reported the oscillations of the radial velocities of limb spicules with the period of 3-7 min. However, their amplitudes were less than 10 km s −1 , which are too small to contribute to our observed line-widths.…”

“…They suggested that the Hα spicules have temperature of 6000 K and nonthermal velocities of ∼25 km s −1 . Follow-up spectroscopic observations of limb spicules under much better seeing conditions were done by Kulidzanishvili (1980) with the 53-cm Lyot coronagraph of Abastumani Astrophysical Observatory and by Hasan & Keil (1984) with Sacramento Peak VTT. From the study of line-of-sight (LOS) velocity and line-width distribution along the axis of spicules, they got a result that, in majority of spicules, the Hα linewidth does not change spatially along the axes of spicules.…”

“…From the study of line-of-sight (LOS) velocity and line-width distribution along the axis of spicules, they got a result that, in majority of spicules, the Hα linewidth does not change spatially along the axes of spicules. Kulidzanishvili (1980) suggested that the line width of the majority of spicules are due to the overlapping of gas moving with relative velocities of 20-30 km s −1 . Nishikawa (1988) used Hα filtergrams to determine the diameter and the motion of limb spicules.…”

Изменение Доплеровских Скоростей И Полуширин Линии D3 Спикул

“…[23]. Ïîçaeå, 3-7 -ìèíóòíûå (ïèê íà 5 ìèí) êîëåáàíèÿ ñïèêóë îòìå÷åíû â [24][25][26][27][28][29]. Êîëåáàíèÿ áûëè èçó÷åíû De Pontieu, Erdélyi & James [30], Khutsishvili et al [31,32] è äðóãèìè.…”