This page (revision-83) was last changed on 02-Feb-2017 13:19 by David R Williams

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[{ALLOW edit EISMainUsers}]
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PB:
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* 14:15 Flows & motions in moss in the core of a flaring active region (David Brooks)
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You can model an active region from the potential field. For SXT or XRT it works quite well hydrostatically. But in TRACE, all the emission is concentrated in the footpoints, but the model shows that there aren't loops. The intensities in the moss match, though, even if the warm, over-dense loops don't.
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Antiochos & co. suggest that the moss emission in large active regions is consistent with steady heating.
One thing I wanted to do is to look at dynamic active regions to see if there are any signatures of dynamics in the moss?
* 14:15 Flows & motions in moss in the core of a flaring active region (David Brooks)
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Use EIS at high-cadence to look at variation in the moss AR 10960. There were 15 M-class flares, 27 C-class flares. So the region is very flare-productive. I've made a movie of the moss region. It's not like the flares are happening away from the moss, they're happening close to or in the core of the region. But the pattern of the moss is very stable. De Pontieu et al. would argue that any variation in the moss is spicules in front of them. We used a study designed with 1-second exposures for a 75-second cadence. Have looked at the properties in little boxes in moss regions.
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See that Vnt is very stable, as is the Doppler velocity and intensity. The flare doesn't really disturb the moss.
PRY: what's the cadence again?
DHB: 75 seconds
HEM: do you have enough counts to pick out changes in the moss?
DHB: you do, yes.
*Looking at the intensities in these boxes: less than 10% but so small that you can see residual orbital variation!
*The velocity doesn't vary by more than 2 km/s over 16 hours
*Non-thermal velocity variation is less than 5% over 16 hours.
Intensities are consistent with a steady or pseudo-steady heating, so the question is, is it showing contribution from steady heating?
HH: you mean the fluctuation of non-thermal velocity is very large?
I would like to show a different result.
Hara: (Small-scale motions at footpoints: signature of coronal heating site)
See large fluctuations in the line width map, where it is dark in TRACE. This region is quiescent, so there is no flaring happening at all.
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There have actually been a couple of flares observed with both RHESSI and EIS. Primarily interested in evaporation.
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*BCS: Was often thought that the stationary component was collected material at the loop top from previous reconnection.
*CDS: Fe XIX, cooler than Ca XIX often showed much slower footpoint velocities
%%invisible
!Science with other, non-Hinode instruments
I’d also like to solicit talks on any of the wealth of cross-observatory data taken over Hinode’s life so far (Hinode-SUMER campaigns, regular CDS co-observing, TRACE co-observing, WHI 2008, etc.) What projects do we have (under-way or recently completed) with these multi-instrument observations that couldn’t otherwise be tackled?
%%
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two scenarios for two diff't electron beam strengths:
# small blueshifts with gentle evaporations
# chromospheric recoil with explosive evaporation caused by much stronger electron beams.
EIS observations, fast rasters.
Part of the loop has only filled at the Fe XXIII and XXIV temperatures. Only above 2MK do we see the blueshifted material. This shift increases with temperature. Fe XXIII may have an Ar blend, but the Fe XXIV seems okay.
Each line profile is symmetric and shifted, except for Fe XXIII and XXIV which still seem to have a dominant stationary component, plus a strong blue-shifted component.
Think there's a small loop with a much larger overlying loop. This paper was submitted about a month ago, and I've just focused on the impulsive phase and the Doppler velocities.
Was interested in looking at flow v as a function of temperature. This is a considerable progression from CDS. First, there's a linear dependence on temperature, and there is a very narrow-T divide between the blue and red-shifted components. The red-shifts are seen up to 2MK, much higher than before. Wei Liu took the Fisher model of a single burst of non-thermal electrons, where as Wei looked at more continuous dumping of energy, and also predicts high-temperature downflows.
In a previous micro-flare observation (B flare) published last year, we also see a high-T downflow. So this high-temperature downflow may be a regular feature in flares; more observations may help us answer this, or whether there's some spectral index dependence.
HEM: can you do densities? wouldn't that be helpful?
RM: Have done the analysis but not the interpretation.
PRY: is the break to do with the detector you're looking at?
RM: don't think so... but it's all in the paper.
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* HEM would be interested to put together a joint EIS XRT temperature distribution.
* LKH thinks there's a disconnect between horizontal magnetic fields
** EIS could potentially do something there
* GAD: SOT discovered spicular material that's moving at very high
* JTM we have great difficulty at getting quantitative information
** JLC is the filter ratio method working quantitatvely
*** think the XRT filter ratio people have confidence, but when you compare that with EIS
** JTM: I just want to know where the hot plasma is
** JLC: if you see it at all in XRT, it's hot, but that's qualitative
** HPW in principle should be able to put these things together. We w
* LKH: Outflow areas: what does Ca II H look like?
* HPW: could SOT provide a measure of the vector magnetic field
* LKH: how do the horizontal magnetic fields impact on heating the atmosphere
* GAD: how accurate are the XRT filter ration?
** And do we know what their temperature responses. We should get XRT to explain how they're getting these.
* HPW: think we should do what Helen has done and get cross-calibrated joint observations
* JTM: does unusual flux emergence have correspondence in EIS data.
* GAD: any energetic stuff seen in SOT: flux cancellation, we could try to tie in with something we see in EIS.
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* 16:20 Line identifications with EIS and CHIANTI (Peter Young)
The chances are in the last few years that if you've observed Fe XI 188.8, yo've probabluy also picked up 188.5 in the same window, so it's a little messy in that region of the spectrum.
* 15:30 Line identifications with EIS and CHIANTI (Peter Young)
* 15:50 Diagnostics with the slot (Ignacio Ugarte)
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If my ident of Fe IX 197 is correct, it's probably a good line for temperature diagnostics.
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Can also "fix" the TRACE temperature response, so it's an important role for EIS to help better science from the imagers.
** Fe VII: normally see that 195 towers above the rest of the spectrum. The Fe VII data most commonly used are normally in the optical, but now working on the EUV lines.
Based on the current ion-balance calculations, it puts Fe VII at logT 5.4. But it's clear that __missed this__
# 11 new line IDs made from EIS spectra (mainly in the LW band)
# 16 new or revised energy levels
*** Diagnostics
Unfortunately no density sensitivity below log ne = 9.0
If you want to put Fe VII in your study, 196.22 is probably the best, and then 195.39 is a factor of two even stronger. Unfortunately, there are a lot of data which have problems and can be out by a factor of two between theory and observations.
Pretty fantastic that you can see 11 consecutive Fe ionisation stages from VII through XVII.
GAD: there's an Fe XXI and XXII line as well as Fe XXIII and XXIV
Also found there are Cr lines, too. Large EM between 5.5 and 5.8 enhances lines in this temperature range. have ID'd Cr VII and Cr VIII
** EIS is very important for doing basic spectroscopy
*** testing atomic data
*** making new identifications
*** benefits existing and upcoming missions' science
* 16:40 Diagnostics with the slot (Ignacio Ugarte)
Wanted to see what else we could get out of the slots.
Compared consecutive slot and slit rasters: similar but different.
Tried to reconstruct 40 gaussians from the slit profile. A LOT of free parameters.
Each of these 40 gaussians has an amplitude, a width, a centroid, and a (constant) background. So I had to fix the parameters. I'm going to assume the same width because they all have the same temperature (it's just an assumption). Also assume that there are no Doppler shifts, that they're centred. So I just fit the amplitudes (justified on the basis of the consecutive raster).
So, we have the raster simulated from the slot. There are differences, but remember that the raster took time to make, and the differences could be of solar origin.
* 17:05 Velocities with the slot (Louise Harra)
Using the slot plus ''TRACE'' and employing a MOSES-like technique. The velocities are very encouraging.
HEM: so it's important that TRACE co-ordinates with EIS?
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What we’ve learned to date on observing with the S-band antenna
* 16:10 Some techniques for observing (David Williams)
* 16:20 Raster stitching (David Brooks)
** Problems
** Some examples of studies that have proven useful in overcoming these problems
** Prospects & challenges for the future:
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** 17:00 Flares (Ryan Milligan)
** 16:25 Flares (Ryan Milligan)
** 16:45 Very active regions (Harry Warren / John Mariska)
* 17:05 Observation Planning - Core Team proposals and HOPS (Len Culhane)
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Small-FOV, high-cadence spectral images are key for good physics.
*** Line profiles from FPs during impulsive phase
*** Measure Doppler and nonthermal velocities as functions of time and temperature
*** How are line profiles related to electron beam parameters
*** n_e measurements.
Wish list:
# < 4-min cadence rasters
# moderate FOV 100 x 100
# fast exposures < 5 seconds
## (originally advertised 1 second exposures)
# line selections:
Core lines, Fe species, at least one n_e sensitive pair
# long duration observations >16 hours per day
# Max millennium ToOs
# not using the flare trigger to increase chance of catching the very early conditions
## what latency is there using the trigger anyway?
## ''seems like it's a second or two from XRT's trigger to EIS
# for RHESSI-specific observations, running EIS only during RHESSI's day?
*** People often write that a spectral window is centred on a given line. Maybe junk the red side of the window, because most high-T lines have blue shifts, but not high redshifts.
*** Are coronal HXR sources the reconnection site? EIS could measure the differences in the pre- and post-flare densities. Perhaps detect reconnection inflows around the source.
*** Observe regions __after__ they've rotated beyond the limb.
*** Impulsive EUV emission
high-cadence (1-second) 266" slot observations
*** resonant absorption of MHD waves
** 17:15 Very active regions (Harry Warren / John Mariska)
Commuted to a discussion about how we might co-ordinate prime flare observations as a test case for prime observations for all major targets.
PRY: if EIS puts a strong message that we want to do one kind of obserbvation
HPW: how do we prioritise our observations when the ARs come back?
PRY: would be good if we came up with an observation
Needs to be freedom -- want to run for long periods of time
Could there be working groups on how to build active region observations, for example? Does there need to be a meeting?
* Active regions
* Quiet Sun
* Observation Planning - Core Team proposals and HOPS (Len Culhane)
''Thursday'' 09:15
Len listed the kinds of class of observation that are proposed by the SSCs after they're gathered from proposers.
Discussions between the EIS SSCs, a more aggressive pursuit of what
HEM: I think what you said about getting feedback is important. One might think of a quick response to the data. ''Good idea''
JLC: there may be a very good reason to run a study several
AI: try to link the eis_plan file into the Wiki so that there's an RSS feed to tell people what EIS is doing.
PRY: is it worth time-limiting these plans? I've probably got enough data.
JTM: I'm a little reluctant to prioritise the 2nd tier, but run numbers would be useful. that would be self-prioritising. A little worried also about polluting the e-mail and webspace with another source of information.
''Suggest somehow placing these files on the Wiki automatically''
HEM would like to know the channel for feedback from proposers.
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17:30
17:15
This page (revision-83) was last changed on 02-Feb-2017 13:19 by David R WilliamsTop