On the problem of spicular oscillations

Abstract

The possibility of the existence of spicular oscillations is discussed in this paper. Ha-spicules show quasiperiodic variations of radial velocities, half-widths and line intensities with a period of 5 min. A grouping of spicules at the solar limb according to positive and negative velocities is found; this is interpreted as the collective oscillation of groups of spicules~ A theoretical analysis is given of the transformation of vertical five-minute oscillations into horizontal ones, in the presence of a magnetic field.

Oscillations and Waves in Solar Spicules

“…Indeed, the oscillations of Doppler velocity in spicules with similar periods were reported by Zaqarashvili et al (2007). If the velocity of the kink wave is polarized in the plane of observation, then it results in the Doppler shift of the observed spectral line (Nikolsky and Sazanov (1967);Pasachoff et al (1968); Kulidzanishvili and Nikolsky (1978); Gadzhiev and Nikolsky (1982); Kulidzanishvili and Zhugzhda (1983); Hasan and Keil (1984); Papushev and Salakhutdinov (1994); ; Kukhianidze et al (2006); Zaqarashvili et al (2007)). However, if the velocity is polarized in the perpendicular plane then it results the visible displacement of spicule axis along the limb (Nikolsky and Sazanov (1967); Nikolsky and Platova (1971); Gadzhiev and Nikolsky (1982); Papushev and Salakhutdinov (1994)).…”

“…Oscillations are more frequently observed in the Doppler velocity, which points towards transversal motions as the observations are performed at the solar limb. The longitudinal velocity component may also take a part in shaping the Doppler velocity oscillations as spicules are Weart (1970) random random Hα Nikolsky and Platova (1971) 50-70 s Hα Kulidzanishvili and Nikolsky (1978) 3-7 min 3-7 min Hα Gadzhiev and Nikolsky (1982) 3-6 min 3-6 min Hα Kulidzanishvili and Zhugzhda (1983) 5-min 5-min Hα Hasan and Keil (1984) 2-3 min > 300 km/s Hα Papushev and Salakhutdinov (1994) 80-120 s 80-120 80-120 > 300 km/s Hα 5-min 5-min EUV Kukhianidze et al (2006) 35-70 s ∼ 80 km/s Hα Zaqarashvili et al (2007) 30-110 s ∼ 110 km/s Hα De Pontieu et al (2007a) 100-500 s 50-200 km/s Ca II generally tilted away from the vertical. However, the transverse component seems to be the more important and determinant component in these oscillations as the visible displacement along the limb is also frequently reported.…”

Observation of kink waves in solar spicules

“…Therefore spicules probably are formed in regions of magnetic field concentration and consequently MHD wave propagation in the solar atmosphere may be traced through their dynamics. Oscillations in spicules with ∼5 min period have been detected by ground based (Kulidzanishvili & Zhugzhda 1983) and recently by space observations (De Pontieu et al 2003;Xia et al 2005). On theother-hand, oscillations in spicules with shorter period have been reported more than 30 years ago by Nikolsky & Platova (1971).…”

Estimation of Spicule Magnetic Field Using Observed MHD Waves by the Hinode Sot

“…Thus it is natural that the MHD wave propagation in the solar atmosphere may be traced through the oscillatory dynamics of spicules. Oscillations in spicules with ∼ 5 minutes period have been detected by ground based and space observations (Kulidzanishvili & Zhugzhda 1983;De Pontieu et al 2003;Xia et al 2005) and are probably connected with global p-modes. On the other hand, the shorter-period oscillations (∼ 1 minute) have been reported by Nikolsky and Platova (1971) as oscillatory displacements of spicule axes at one particular height.…”