Nonthermal Mass Motions within the High-Temperature Plasmas above a Complex Solar Active Region

Abstract

We report on mass motions in high-temperature plasmas at radial distances of 1.06-1.20 R_solar corresponding to 3.3×10⁴-1.3×10⁵ km above the west solar limb. The observations were conducted over a 53 hr time period while a complex active region moved across the west solar limb. We found that the nonthermal mass motions in the 2.6×10⁶-6.6×10⁶ K plasmas that were imaged along the slit were in the 20-35 km s^-1 velocity range. The magnitude of the nonthermal mass motions was independent of the plasma temperature or its height above the limb. We also found that the emission measure distribution within the 2.6×10⁶-6.6×10⁶ K plasma regimes did not change during most of the observations, an indication that on the average the temperature distribution among the various plasma volumes along the line of sight stayed unchanged.