Empirical Densities, Kinetic Temperatures, and Outflow Velocities in the Equatorial Streamer Belt at Solar Minimum

Citations Over TimeTop 10% of 2002 papers

Abstract

We use combined Ultraviolet Coronagraph Spectrometer and Large Angle Spectroscopic Coronagraph data to determine the O5+ outflow velocities as a function of height along the axis of an equatorial streamer at solar minimum and as a function of latitude (at 2.3 R☉ from Sun center). The results show that outflow increases rather abruptly in the region between 3.6 and 4.1 R☉ near the streamer cusp and gradually increases to ~90 km s-1 at ~5 R☉ in the streamer stalk beyond the cusp. The latitudinal variation at 2.3 R☉ shows that there is no outflow (within the measurement uncertainties) in the center of the streamer, called the core, and that a steep increase in outflow occurs just beyond the streamer legs, where the O VI λ1032 intensity relative to H I λ1216 (Lyα) is higher than in the core. Velocity variations in both height and latitude show that the transitions from no measurable outflow to positive outflow are relatively sharp and thus can be used to infer the location of the transition from closed to open field lines in streamer magnetic field topologies. Such information, including the densities and kinetic temperatures derived from the observations, provides hard constraints for realistic theoretical models of streamers and the source regions of the slow solar wind.

Related Papers

• → Soil Water Diffusivity Determination using a New Two‐Point Outflow Method(2011)10 cited
• → Laboratory investigation on the influence of factors on the outflow temperature from stratified reservoir regulated by temperature control curtain(2020)7 cited
• Accessory cusp: Cusp of carabelli - A brief review(2013)
• Impacts of the Vertical Position of Outflow on the Outflow of Pollutant in Reservoir(2006)
• Analysis on the Abnormal Changes of Outflow,O_2+Ar,N_2 and He in No.1 Spring at Wushan Station(2008)