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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0201

CME Heating and Current Sheets

plan term


@ @


 name : Miralles, Landi, Murphy, Reeves, Raymond @  e-mail : mmiralles[at]cfa.harvard.edu

contact person in HINODE team

 name : Landi (EIS), Reeves (XRT) @  e-mail : elandi[at]umich.edu

 abstract of observational proposal
Studies of the initial phases of CME heating and of the formation of the current sheet (CS) after the ejection are of crucial importance for understanding the physics behind CME ejections. In recent studies, Landi et al (2010, 2011) observed a CME event with a suite of instruments including EIS and XRT and were able to study the thermal structure of the ejecta and monitor the evolution of the CS that formed afterwards. They found that:

1 - The CME core were formed by three distinct plasmas, with different density and temperature, which ranged from Log T=5.1 to Log t=5.7

2 - The CME core was enveloped in a much hotter plasma with temperature in excess of 3MK.

3 - The current sheet observed afterwards had lower temperature than the surrounding corona, and temperatures of ~2-3MK; very hot plasma was not observed.

These results are very important for quantitative, predicting models of CME initiation and energetics, but they need to be improved. In fact, the identification of the hot plasma was made through the only XRT filter available in the observations (Al-poly) and no detailed plasma diagnostics could be carried out to determine its physical properties. The measured temperature and densities of the current sheet contradict all current models, but they were carried out at low altitudes where significant contamination from a post-CME arcade decreased the accuracy of the measurements.

Here we propose to carry out a series of "CME-watch" simultaneous  observations with EIS and XRT on limb active regions that have a potential for CME ejections; these observations are designed to maximize the diagnostic capabilities of the data, and minimize contamination from background sources.

 request to SOT

 request to XRT
POINTING: Time series of images at the solar limb

TARGET: limb active region

FIELD OF VIEW: 512x512

EXPOSURE TIME: Long exposure time (AEC setting = 2)

FILTERS: Ti/poly and Thin-Be

CADENCE: 1 minute preferred, 2 minutes acceptable.

OBSERVING SEQUENCE: The standard AR Tracking program with Filter Ratio, such as XOB #189F (AR Standard-A(Filter-Ratio) with PFB, thin-Be, thick Al and Al/Poly context, 384x384 at 1064 1048, 60s cad),  modified to have a 512x512 field of view and AEC=2, would be good.

Simultaneous observations with EIS

 request to EIS
POINTING: Sit'n'stare observations at the solar limb near the equator

TARGET: limb active region

OBSERVING SEQUENCE: needs to download with reasonable cadence the entire EIS wavelength range. Suggested sequences (already existing in the database):

EIS_FULL_CCD_SINGLE           2"x512"     300s exp.time
EIS_WHI_CH_LIMB               2"x512"     600s ext.time

EXPOSURE TIMES: 150 s (preferred), 300s-600s (backup plan)

Simultaneous observations with XRT

 other participating instruments

DURATION: This study should be run for several days to maximize the probability of catching a CME. During each day, this study should be run for several hours (from 6 hours [minimum] to 12 hour [preferred]).

If no CME is detected, the observations will be anyway useful to study active regions.

POINTING: E. Landi and M. P. Miralles will specify pointing.

TARGET: Flaring AR seeing on disk to be observed at the limb.

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