1 / 13

PCTR Physics and “Chewy Nougats*”

PCTR Physics and “Chewy Nougats*”. SSL, UC Berkeley. * This nomenclature due either to Greg Slater or Sam Freeland, SXT data pioneers (most likely Greg). What is the prominence-corona transition region (PCTR)?.

otto
Download Presentation

PCTR Physics and “Chewy Nougats*”

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PCTR Physics and“Chewy Nougats*” SSL, UC Berkeley * This nomenclature due either to Greg Slater or Sam Freeland, SXT data pioneers (most likely Greg)

  2. What is the prominence-corona transition region (PCTR)? • Analogous (?) with the horizontally stratified ordinary TR, it separates the cold prominence from the hot corona • It must be closely aligned with the separatrix between filament fields and cavity fields • There are several approaches to understanding it: DEM, radio, filaments, hydrodynamic, MHD, each seemingly with its own literature

  3. Behind the DEM approach Vernazza, Avrett & Loeser 1981

  4. Different views of the prominence- corona transition region Kucera & Landi, 2008 Cirigliano et al. 2004 Heinzel et al. 2008 Antiochos & Klimchuk 1991

  5. “Chewy Nougat” There is a hot (soft X-ray) brightening around the cold prominence Hudson et al. 1999

  6. The original nougat as seen on the disk Some polar nougats found by Okumura

  7. Multiwavelength Nougat (thanks, Brigitte!) EIT 284 EIT 195 EIT 304 cavity cavity Filament material in dips of magnetic field lines prominence (Aulanier)

  8. Nougats and flares?

  9. The Nougat’s basic messages • If the PCTR is hotter than the corona surrounding it, the PCTR is unlikely to depend on static conduction as in normal TR models. • We don’t really know if the nougats observed by SXT were hotter than the cavity, since the cavity temperature is hard to determine • A filamentary (Chiuderi-type) PCTR would need to extend to heights well above the cold prominence material • The PCTR is likely not to be a TR at all, just loops

  10. Is a “PCTR” as suchobservable or even relevant? • Transport perpendicular to the field may be negligible; “conductive heating is completely insignificant”* • If so the TR-temperature regions may be physically separated from the prominence • Large perpendicular gradients of gas pressure would be expected even at low plasma beta *Anzer & Heinzel 2008

  11. Is “magnetic reconnection” observable or even relevant? • The boundary between corona and prominence should correspond to a current system, which can support instabilities • The standard reconnection model of a flare/CME involves shocks and jets, whose heating is not local

  12. Conclusions • The “Nougat” signature may just be space-filling hot branches of the actual prominence fields • Need a proper electrodynamic theory to understand the true (perpendicular) boundary structure in the corona • Need high resolution and sensitivity to understand how hot loops relate to prominence-bearing fields • The term “PCTR” is probably misleading, except to a spectroscopist* *n.b. PCTR ≈ PETR

  13. Challenge • Is it possible to show that the cavity itself does not consist of just the hot branches of the prominence field?

More Related