（Seminar by Rob Rutten from Netherlands）
报告时间（Date & Time）：Oct. 24 (Wednesday) 10:00-12:00
报告嘉宾(Presenter)：Prof. Rob Rutten
报告题目(Title)：Heating above and around network near a coronal hole
Normal07.8 磅02falsefalsefalseEN-USZH-CNX-NONE报告地点(Venue): South 208
Even in very quiet areas the solar chromosphere contains ubiquitous heating events in which its main constituent, hydrogen gas, becomes ionized. They tend to be small-scale and short-lived, hence difficult to identify. In subsequent cooling and hydrogen recombination the opacity of H-alpha can maintain very high values, enormously above the thermal equilibrium value, due to slow collisional settling of Ly-alpha. An outspoken example observed with the Swedish 1-m Solar Telescope was analyzed in detail by Rutten & Rouppe van der Voort (2017A&A...597A.138R) and called a "contrail" in analogy with airplane contrails on our sky. More generally, the extraordinary fibrilar appearance of the chromosphere in H-alpha may result from such recombination over-extinction.
In this analysis of the same data I proceed to full-field and full-duration analysis. I use statistical differential analysis of H-alpha and Ca II 8542 to show evidence that many slender or unresolved extended structures spreading out from network over surrounding internetwork mark spicule-II-like heating events, with as telltale indicator that Ca II ionizes. They tend to produce coronal connectivity over long distances and also tend to harbor subsequent cooling recombining gas producing dark H-alpha features minutes later. However, in the inner regons of chromospheric network I find heating going straight up and dominating local coronal EUV emissivity. In these CaII does not yet ionize, presumably from larger density at deep heating onset which also produces larger emissivity (mass loading) in the EUV SDO/AIA diagnostics.
These two classes of heating appear distinct, but the underlying heating mechanisms may be the same and only differ in having lower onset height at more vertical and denser field topography.
报告嘉宾简介(Brief introduction to the presenter):
Prof. Dr. Robert Rutten (Lingezicht Astrophysics, Deil, The Netherlands)
1961: Eindexamen Gymnasium-beta, Het Nieuwe Lyceum, Bilthoven, The Netherlands
1968: Drs. Wis- en Natuurkunde, Rijksuniversiteit Utrecht, The Netherlands
1976: Dr. Sterrenkunde, Rijksuniversiteit Utrecht, The Netherlands
Employment at Utrecht University, The Netherlands
1963 - 1965: education assistant
1966 - 1968: research assistant
1968 - 2007: tenure-track scientist, staff member, senior scientist, program leader solar physics, project scientist Dutch Open Telescope
2007 - present: emeritus scientist