UVCS WG ON
Theoretical Models of Helmet Streamers

Chairperson:

Group Coordinator:

Main scientific purposes:

To develop a self-consistent theoretical description and understanding of the internal thermal and dynamical structure of helmet streamers, using observational constraints provided by UVCS through, and in close collaboration with, the Working Group on Empirical Models of Helmet Streamers.

1. Spatial structure - what determines it, and why it matters: Streamer magnetic topology Sheet currents vs volume currents Effects of nonthermal heating High- vs low-velocity outflows "Confined" plasma flows in the closed field region Importance of, and magnetic configuration of, the streamer cusp Origin and consequences of high ion temperatures Implications of compositional gradients
2. Temporal evolution - why it occurs, and how fast: Gradually changing boundary conditions (e.g., migrating surface fields) Changes in the volumetric heating rate Magnetic reconnection Coronal transients, within and without Response to global coronal changes

Current Members:

• Buergi, A.
• Corti, Gianni
• Esser, Ruth
• Fineschi, Silvano
• Gibson, Sarah
• Hoeksema, Todd
• Hollweg, Joe
• Kopp, Roger (chairperson)
• Kundu, Mukul
• Maccari, Lisa
• Noci, Giancarlo
• Poletto, Giannina
• Raymond, John
• Romoli, Marco
• Spadaro, Daniele
• Suess, Steve
• Svestka, Zdenek
• Wang, A-H.
• Wang, Y-M.