H_αloops in solar active regions

Plasma Velocities in the Solar Corona and Transition Region

“…As it was shown in Porfir'eva (2003b), and the ξ for the X-ray flares with T 10 7 K is equal to (161±5) km s −1 but the values of ξ vary in the wide range from 90 to 300 km s −1 . For the weaker flares with T 10 7 K ξ = (146 ± 8) km s −1 (symbol ), i.e.…”

“…Spectral line profiles, forming in the temperature range from 1×10 4 K to 3×10 7 K, contain information of matter velocities in different layers and coronal structures. Literature data on observations, obtained from cosmic stations and on the ground, and results of interferometric observations during several solar eclipces (see Delone, Yakunina & Porfir'eva (2003b) have been used.…”

“…The ξ values for the chromosphere, transition region and lower corona (symbol ) were taken from Chae et al (1998). In addition the data for the quiet corona (symbol +) were taken from Delone, Yakunina & Porfir'eva (2003b), Doschek & Feldman (1977), and Raju et al (2000). We can see that the nonthermal velocity increases when the temperature increases, reaching its maximum equal to ∼ 30 km s −1 when T=3 × 10 5 K, and then begins to fall to the value of about 20 km s −1 in the lower corona.…”

“…As it is discussed by Delone et al (2003a) the random velocities in CHs in average are greater than in quiet corona. The values of ξ for nonflaring active regions (ARs)(symbol ), being in a relatively quiet station, were taken from Delone, Yakunina & Porfir'eva (2003b), Saba & Strong (1991), Sterling (1997), . We can see that the nonthermal velocities and temperature in the ARs are greater than in the lower quiet corona.…”

“…We can see that the nonthermal velocities and temperature in the ARs are greater than in the lower quiet corona. For the flaring corona the data were taken from Delone, Yakunina & Porfir'eva (2003b) , Ranns et al (2001), and Doschek, Mariska & Strong (1994) …”