[Loops] type II spicule paper

Tue Jul 31 09:24:42 MDT 2012

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 at solar.physics.montana.edu [mailto:loops-
> >> bounces at solar.physics.montana.edu] On Behalf Of Petrus Martens
> >> Sent: Tuesday, July 31, 2012 10:33 AM
> >> To: loops at 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 at nasa.gov
> >> <mailto:James.A.Klimchuk at 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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> >>>>> https://mithra.physics.montana.edu/mailman/listinfo/loops
> >>>>>
> >>>>
> >>>>
> <martens.vcf>_______________________________________________
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