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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0069

WHI ToO #2: Equatorial Coronal Hole Study

plan term


@ @


 name : Miralles @  e-mail : mmiralles[at]cfa.harvard.edu

contact person in HINODE team

 name : Sterling @  e-mail : alphonse.sterling[at]nasa.gov

 abstract of observational proposal
To understand the origin of the solar wind from low-latitude coronal holes, including coronal hole boundaries by characterizing the physical properties of the coronal plasma (temperature, density, abundance, outflow velocity) with coordinated multi-spacecraft and ground-based observations in order to investigate the physical processes that lead to the origin of the solar wind.

These observations would improve on previous studies by coordinating observations with a battery of instruments providing co-spatial, co-temporal and good coverage in heliocentric distance from the solar disk to solar wind locations over 1 AU.

This study will combine spectroscopy, imaging, IPS and in-situ data to derive the plasma physical properties and the geometry of the coronal hole. The combination of these measurements would provide a 3-D view of solar wind properties.

We are interested in observing holes producing fast or slow wind. Fast solar wind speeds above 600 km/s have been reported for large equatorial coronal holes (Nolte et al. 1976, Miralles et al. 2001a). Slower solar wind speeds were reported for low-latitude holes of smaller size, between 300 and 600 km/s, near solar minimum (Neugebauer et al. 1998).

We are also interested in studying the temporal evolution of coronal and solar wind properties by monitoring plasma properties at different heights in the corona and in the solar wind during the campaign. Jets and plumes have been studied on polar holes, but there are not many studies of those in low-latitude holes. The contribution and role of both, plumes and jets, to the solar wind is still unknown. This campaign will also emphasize on identifying and tracing jets and plumes from the solar surface into the accelerating solar wind and determining their physical properties as a function of height and time.

 request to SOT
Hinode/SOT -- campaign contact: Alphonse Sterling (and SOT CO)
Standard FG CaII, photospheric, and magnetic line images, all  at moderate cadence.

 request to XRT
Hinode/XRT -- campaign contacts: T. Sakao.
The primary observational interest is to take a series of long exposure (16s, or longer) XRT images with relatively thin filters (Ti-poly, or those more sensitive to low temperature coronal plasmas) with high or moderate exposure cadence (once in every 60s, or higher), in 512x512 FOV with 1x1 pixel binning, to identify sources of plasma outflows at or around low-latitude coronal holes. Occasional exposures with two different filters to obtain line-of-sight-averaged filter-ratio temperatures will also be performed. This would be made with Al-poly and Ti-poly filter pair.

 request to EIS
Hinode/EIS -- campaign contacts: Enrico Landi
The EIS sequences are different according to the target:
Off-disk pointing:  EL_FULL_CCD_RASTER EL_ABUND_LOOP_SUMER and EL_ABUND_PLUME_SUMER are identical except for the exposure time and the slit. They are a 50"-wide raster that includes enough lines  to carry out plasma diagnostics in low-intensity areas. Being a raster, they are good to observe
on-disk coronal holes by running them sequentially over large areas. EL_FULL_CCD_RASTER is a long-exposure, 12x512 arcsec raster with the full EIS wavelength range, and is excellent for off-disk observations. It can be run at different distances from the limb to map the evolution of the coronal hole with height.

 other participating instruments
Other Instruments include:
Various. Consult WHI web page for details.

Further Details:
More details can be found at the following page:
(especially under "targeted observing plans").

Note:  The content of this proposal is the same as that of DeForest (WHI One-Week Campaign #3).  During campaign weeks 1, 2, or 4 this program is to be run as a ToO, and Miralles is the final authority on pointing choices  etc., during those times.  During campaign week 3, this program should be run as a standard HOP, and DeForest will be in charge at that time.  

When appropriate ToO is available, during the campaign period 20 March - 16 April 2008.

Target candidates will be proposed by M. P. Miralles. An update on the list of candidates will take place one solar rotation prior to campaign Carrington Rotation (see below). Another update will take place 1/2 rotation before observations and will be communicated to the other instruments/campaign coordinators involved. Target could be at any latitude, preference would be given to holes that are co-temporal with campaign and cleaner line-of-sights. Although coronal holes at lowest latitudes are also desirable for correspondence with some in situ measurements.

Observation Time Period:
Specific times TBD; see main campaign page for updates.  Prefer the length of time to be about six hours per day, with planning based on repeated 1-2 hour blocks.  These times will likely include the standard WHI time periods.

Target Observations: Observations will take place, at least, in three positions: on-disk, disk-center, and at the limb (or on-disk and both limbs). These will be determined once we know the time allocated for this target of opportunity. Duration of the observations will depend on size of hole. Typical observing lengths of 3-5 days are usually required to include the characterization of regions in the foreground and background of the coronal hole line-of-sight.

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