Can the Superposition of Evaporative Flows Explain Broad Fe XXI Profiles during Solar Flares?
Polito, Vanessa, Paola Testa, and Bart De Pontieu, Can the Superposition of Evaporative Flows Explain Broad Fe XXI Profiles during Solar Flares?, ApJ, 879, L17 (2019) (ADS)
(click on the image for a larger version)
We are striving to understand "chromospheric evaporation", the name
given to the process by which flares can fill coronal magnetic traps
with plasma that somehow appears to get hot as it expands from the
chromosphere.
How can this happen?
It is an essential part of any flare model, and yet not well explained
physically yet.
Perhaps it is connected with the geometry; if there is sub-telescopic
structure, then the physical parameters are difficult to disentangle.
This cartoon deals with the geometry of unresolved structures in these
magnetic traps (note that two panels have been omitted here).
The faint purple bands represent flare ribbons, and this cartoon is a
classic example perspective perplex in grafting 2D concepts into a 3D
flare world.
Interestingly, the well-defined line widths of the Fe XXI evaporation
flows imply temperatures much higher than the electron temperatures
in the hot loops that develop.
See the Brannon-Longcope
cartoon for another take on this complexity.
We are striving to understand "chromospheric evaporation", the name given to the process by which flares can fill coronal magnetic traps with plasma that somehow appears to get hot as it expands from the chromosphere. How can this happen? It is an essential part of any flare model, and yet not well explained physically yet. Perhaps it is connected with the geometry; if there is sub-telescopic structure, then the physical parameters are difficult to disentangle. This cartoon deals with the geometry of unresolved structures in these magnetic traps (note that two panels have been omitted here). The faint purple bands represent flare ribbons, and this cartoon is a classic example perspective perplex in grafting 2D concepts into a 3D flare world. Interestingly, the well-defined line widths of the Fe XXI evaporation flows imply temperatures much higher than the electron temperatures in the hot loops that develop. See the Brannon-Longcope cartoon for another take on this complexity.