Hugh,
Actually, my use of "Scudder" was shorthand for "plasma kinetic effects." I don't regard these as unrelated to "heating" in general; I doubt that a paper can draw general conclusions in this area without a discussion of that physics.
Given the densities in spicules, I doubt that kinetic effects will play a significant role. What specifically did you have in mind that would invalidate my analysis?
I note that your definition of evaporation is inconsistent with our normal usage for flares, where non-thermal particles can do the dirty work. But perhaps I will read on past this point!
Remember, this paper is about spicules, not evaporation! I do make the side point that spicules and heat flux driven evaporation are fundamentally different. I also make the point that no non-thermal beam flare simulations that I, George Fisher, or Joel Allred are aware of produce anything that resembles a spicule. Do you know of any that we don't?
Thanks, Jim
Cheers
Hugh
On 31 Jul 2012, at 16:45, Klimchuk, James A. (GSFC-6710) wrote:
Right, Piet. They are totally unrelated.
Jim
-----Original Message----- From: loops-bounces@solar.physics.montana.edu [mailto:loops- bounces@solar.physics.montana.edu] On Behalf Of Petrus Martens Sent: Tuesday, July 31, 2012 10:33 AM To: loops@solar.physics.montana.edu Subject: Re: [Loops] type II spicule paper
On 7/31/12 8:27 AM, Hugh S. Hudson wrote:
It may be a great paper, but why is there no citation of Scudder's work?
Would have been useful. I don't think Jim's results invalidate Scudder's results though.
Piet
Hugh
On 31 Jul 2012, at 16:12, Petrus Martens wrote:
Hey, great paper! Glad that someone looked into that.
Cheers,
Piet
On 7/31/12 7:47 AM, Klimchuk, James A. (GSFC-6710) wrote:
Dear friends,
You might be interested in my recent paper on "The Role of
Type II Spicules in the Upper Solar Atmosphere," which can be downloaded at http://arxiv.org/abs/1207.7048
Cheers,
Jim
ABSTRACT:
We examine the suggestion that most of the hot plasma in the Sun's
corona comes from type II spicule material that is heated as it is
ejected from the chromosphere. This contrasts with the traditional
view that the corona is filled via chromospheric evaporation that
results from coronal heating. We explore the observational
consequences of a hypothetical spicule dominated corona and conclude
from the large discrepancy between predicted and actual observations
that only a small fraction of the hot plasma can be supplied by
spicules (<2% in active regions and <5% in the quiet Sun). The
red-blue asymmetries of EUV spectral lines and the ratio of lower
transition region (LTR; T<0.1 MK) to coronal emission measures
are both predicted to be 2 orders of magnitude larger than observed.
Furthermore, hot spicule material would cool dramatically by
adiabatic expansion as it rises into the corona, so coronal heating
would be required to maintain the high temperatures that are seen at
all altitudes. The necessity of coronal heating is inescapable.
Traditional coronal heating models predict far too little emission
from the LTR, and we suggest that this emission comes primarily from
the bulk of the spicule material that is heated to <0.1 MK and
is visible in He II (304 A) as it falls back to the surface.
James A. Klimchuk
NASA Goddard Space Flight Center
Solar Physics Lab, Code 671
Bldg. 21, Rm. 158
Greenbelt, MD 20771
USA
Phone: 1-301-286-9060
Fax: 1-301-286-7194
E-mail: James.A.Klimchuk@nasa.gov
mailto:James.A.Klimchuk@nasa.gov
Homepage:
https://sedupdate.gsfc.nasa.gov/sed/index.cfm?fuseAction=people.jump
Bio&&iPhonebookId=15844
No endorsement by NASA is implied for any correspondence related to my role as an officer of professional organizations (American Geophysical Union, International Astronomical Union, American
Astronomical Society).
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