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Re: ?Xrt Tadpoles?
Hi Sabrina,
Very nice movie!! Why I asked about this is that I have been
approached by Li-Jen Chen at UNH about the research. We have a group
here in the area- New England Space Science Consortium (NESSC) that is
writing up several papers on comparative physics in the magnetosphere
versus the sun. She works in
the magnetosphere and have seen- excuse the expression- tadpole like
structures that end up connected with electron acceleration as magnetic
islands. She asked if I could look at the XRT data and coordinate Rhessi
data to see if the phenomena in the sun in similar.
I of course do not want to interfer with your thesis work but would like
to explore this topic.
Let me know what you think,
Kelly
On Thu, 10 May 2007, Sabrina Savage wrote:
> Hello all,
>
> On short notice, I do have an example movie of some sharpened supra-arcade downflows on
> my site: http://solar.physics.montana.edu/savage/Solar.html . This one is the
> well-known TRACE 020421 flare, however, we have several SXT examples and even a few XRT
> ones. The last active region that just came across the disk even produced a nice example
> of a downflow during one of its small flaring events. As David mentioned, I will be
> presenting these results in my poster at the AAS meeting in May.
>
> Cheers,
> Sabrina
>
>
>
> -----Original Message-----
> From: "David McKenzie" <mckenzie@mithra.physics.montana.edu>
> Sent 5/9/2007 6:01:51 PM
> To: "Ed Deluca" <edeluca@cfa.harvard.edu>
> Cc: "Kelly Korreck" <kkorreck@cfa.harvard.edu>, "Leon Golub" <lgolub@cfa.harvard.edu>,
> "Patricia Jibben" <pjibben@head.cfa.harvard.edu>, "Loraine Lundquist"
> <llundquist@cfa.harvard.edu>, "Steve Saar" <saar@head.cfa.harvard.edu>, "Antonia
> Savcheva" <asavchev@cfa.harvard.edu>, "Jonathan Cirtain" <jcirtain@cfa.harvard.edu>,
> "Monica Bobra" <mbobra@head.cfa.harvard.edu>, "Mark Weber" <mweber@cfa.harvard.edu>, "Tom
> Metcalf" <metcalf@cora.nwra.com>, "Kathy Reeves" <kreeves@cfa.harvard.edu>, "David
> McKenzie" <mckenzie@mithra.physics.montana.edu>, "Sabrina Savage"
> <savage@mithra.physics.montana.edu>
> Subject: Re: ?Xrt Tadpoles?
>
> Responses to some of the many comments in this thread:
>
> > Metcalf and Kathy have looked at RHESSI/XRT joint obs. I think
> > RHESSI missed the X-flares seen by XRT, is this true?
>
> I checked with Hudson and Krucker back in December, and RHESSI has a
> little from 12-Dec, and more from 13-Dec. See
> http://sprg.ssl.berkeley.edu/~tohban/browser/?show=grth+qlpr+qlprr&date=20061213&time=022816
> Haven't followed up with them since, though.
>
>
> >> > We have seen them in both of the X-flares (on the disk). I don't
> >> > think we have seen
> >> > this on the disk with TRACE or Yohkoh.
>
> Yohkoh did see them as far onto the disk as longitude=32degrees (McKenzie
> 2000, Sol.Phys., 195, 381), though they are certainly easier to see at the
> limb.
>
>
> >> > The argument is that they are voids maybe associated with empty flux
> >> > ropes contracting through the hot plasma.
>
> The strongest evidence for 'voids' is spectroscopic observations from
> SUMER (Innes et al. 2003, Sol.Phys., 217, 247), in which the downflowing
> features showed (a) no emission in 3 different temperatures, and (b) no
> absorption of neutral hydrogen. No emission + no absorption = no density.
>
> As for 'shrinking flux tubes', we based this on the facts that (a) they
> move down into the top of the arcades, and no further; (b) the motions are
> not radial to the sun, and thus are not aligned with the gravitational
> vector; and (c) in flares with dark downflows, we also often see
> X-ray-emitting features with the same motions (speed and direction) and
> sizes. The emitting, shrinking things seem to be vaguely loop-shaped.
> Other than flux tubes shrinking to relax magnetic tension, it's difficult
> to explain plasma voids moving downwards into the top of an arcade.
>
> >> > > Is anyone working on this or knows the dates of the data?
>
> As I mentioned, this is Sabrina's thesis project. She's developed some
> techniques for automatically detecting the flows, and we've produced some
> results assigning magnetic fluxes to the individual flux tubes. Sabrina
> will be presenting her work at SPD; see her abstract online. Sabrina, do
> you have an enhanced movie of the XRT SADs you could share with the group?
>
> McKenzie's XRT movies are a password-protected webpage at
> http://solar.physics.montana.edu/mckenzie/Temp/
>
> [The username is xrtco, the password is too, 2x]
>
>
> >> > > Also is there an XRT data/science email list?
>
> xrt_science@head.cfa.harvard.edu
>
>
> Incidentally, it's the SUMER result that makes me strongly object to the
> 'tadpoles' nomiker. 'Tadpole' suggests a blob of higher density, whereas
> the data clearly indicate an absence of density.
>
> Maybe I ought to come out and give a seminar or something....
>
> __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __
> David E. McKenzie, Ph.D. mckenzie@solar.physics.montana.edu
> Montana State University Phone: (406) 994-7843
> Dept. of Physics http://solar.physics.montana.edu/mckenzie
> "Luceo, non uro"
> __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __
>
>