HOP 0114

abstract of observational proposal

Goal - Observe properties of coronal prominence cavities to inform and　constrain cavity modeling efforts. Useful observations would include both quiet cavities and, if circumstances allow, eruptive or pre-eruptive cavities. With a combination of Hinode, AIA, and the Coronal Multi-channel Polarimeter (COMP) at MLSO we can obtain information about evolution of temperature, magnetic field, and dynamics with which to test models of prominence cavities and CME eruptions.

Hinode provides essential information concerning density, temperature, dynamics of cavities. We propose to run HOP 114, a relatively new HOP that has only been run once before. We are currently working on that data set and presented it at the Fall 2011 AGU meeting (Kucera et al. 2010). The design of HOP 114 is based on our experience with previous Hinode data used to measure line of sight velocities and electron densities in cavities (Schmit et al. 2009 and Schmit & Gibson 2011) and cavity temperature structure (Reeves et al. and Kucera et al. in progress).

New observations would provide Hinode cavity data in conjunction with both SDO/AIA data, providing high cadence images in a range of wavebands produced at various temperatures, and MLSO/COMP data, providing information relating to both flows and magnetic field. This would be a powerful combination for studying coronal cavities, particularly in forward modeling efforts. COMP has been operating regularly at MLSO since October 2010. Early run data demonstrated its usefulness for cavity observations (Dove et al. 2011)
At present only one cavity data set exists containing data from the three Hinode instruments and AIA, and there are no joint, optimized observations of a cavity with both Hinode and COMP.

request to SOT

Priority 3:
BFI: Ca II H-line
Exposure: 500 ms
FOV: 2048x2048
Binning: 2x2
Cadence: 600 s
Objective: Characterize the location of prominence material.
Data/hour: 24 Mb
Note: Low cadence SOT observations of the prominence are essential to be able to discern regions of absorption as seen by EIS.

NFI: H-alpha +/-208 mA dopplergram mode
Exposure: 500 ms
FOV: 1408 x1408
Binning: 2x2
Cadence: 40 s
Objective: Velocity measurements of the prominence to be compared to EIS velocities in cavity
Data/hour: 180 Mb
Note: High cadence dopplergrams are unnecessary for the total HOP duration. It is important that the dopplergrams and the EIS sit-and-stare study to occur simultaneously.

request to XRT

Priority 2:
Filters and exposure times:
Al-mesh (8 sec)
Al-poly (12 sec)
C-poly (16 sec)
Ti-poly (16 sec)
Al-poly + Ti/poly (23 sec)
thin Be (65 sec)

Compression: DCPM (lossless)
FOV: 768x768
Binning: 2x2
Cadence: 5 min
Objective: DEM analysis of cavity
Data/hour: 20 Mb

Note: Long exposure times are requested, but they can be shortened if bright features exist on the disk and safety of the instrument is an issue. Cadence can be lengthened to ~10 minutes if necessary for telemetry.

request to EIS

Priority 1:
Core study: gdz_plume1_2_300_50s
Number of runs: Ideally run twice. Run once if under tight time or memory constraints.
EIS Window placement: Center just above the prominence. If no prominence is visible center above where prominence would be.
FOV: 300”x512”
Run time: 1h05m per study
Objective: DEM analysis of cavity and PCTR
Data Size: 245 Mb per study

remarks

Target: A Target of opportunity - a clearly visible cavity on the solar limb. The associated filament channel must be aligned so that the cavity is likely to remain visible between target selection and observations.

Time Window: We would like to observe promising cavities over a number of days for 4-6 hours at a time, centered around the prime MLSO observing time of 18-22 UT. This would allow us to model the quiescent cavity in three dimensions. In the case of cavity eruption we would observe changes associated with gradual onset of eruption.

References

Journal Papers:
Dove, J., Gibson, S., Rachmeler, L. A., Tomczyk, S., & Judge, P. 2011, ApJ, 731 L1, "A Ring of Polarized Light: Evidence for Twisted Coronal Magnetism in Cavities"
Schmit & Gibson 2011 ApJ 733, 1 "Forward Modeling Cavity Density: A Multi-instrument Diagnostic"
Schmit, D.J., Gibson, S.E., Tomczyk, S., Reeves, K.K., Sterling, A.C., Brooks, D.H., Williams, D.R., & Tripathi, D. 2009, ApJL, 700, 96 "Large-Scale Flows in Prominence Cavities"

Conference Presentations:
Kucera, T. A.; Berger, T. E.; Boerner, P.; Dietzel, M.; Druckmuller, M.; Gibson, S. E.; Habbal, S. R.; Morgan, H.; Reeves, K. K.; Schmit, D. J.; Seaton, D. B. "Space Based Observations of Coronal Cavities in Conjunction with the Total Solar Eclipse of July 2010", AGU Dec. 2010 (used HOP 114 data. Paper planed for future).

Other papers in progress:
Reeves et al. Analysis of hot cavity cores with Hinode/XRT data from Summer 2008
Kucera et al. Cavity temperature modeling of Aug. 2007 data using Hinode/EIS data