MAX MILLENNIUM OBSERVING PLAN 017


TITLE

Filament/Prominence Likely to Erupt

AUTHORS

Identify the lead author (who will lead the plan definition, scheduling, target selection, and subsequent data analysis) and key participants from various GBOs and space missions. List names and e-mail addresses.

William Marquette (wmarquette25@gmail.com) Helio Research
Sara Martin (sara@helioresearch.org) Helio Research

VERSION

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Version 1: DRAFT OF MARCH 6

SUMMARY

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This plan describes context and filament/prominence observations from ground-based and space-based instruments and observatories appropriate to solar conditions that are likely to produce filament/prominence eruptions. It describes the circumstances under which the Max Millennium Chief Observer will declare a Filament/Prominence Watch.
  • Goal: To obtain multi-wavelength imaging and spectroscopic observations before, during and after eruptions of filaments/prominences and the associated CMEs and ICMEs. 
  • Approach: In a manner appropriate to each instrument, observatory, and spacecraft, to observe, if at all possible, the small and large scale environment of a filament/prominence identified in a Filament/Prominence Watch message from the Max Millennium Chief Observer distributed to the Max Millennium Message of the Day list. 

  • SCIENCE QUESTIONS

    Ø    Slow Rise of Filaments

    1. Is there a quantitative relationship between the rate of slow rise of filaments and rate of slow rise of CMEs?

    2. What is the minimum rate of change in height required to recognize the beginning of a long-term slow rise?

    3. How long after the formation of the first filament threads is the slow rise detectable for active region and quiescent filaments?

     

    Ø    Indirect Evidence of Filament Cavities

    1. Does the chromospheric structure in filament channels give any evidence of the existence of the filament cavity in the above corona?

    2. Is there evidence that the bubbles found to be prevalent in Hinode observations   contribute magnetic field to the filament cavity?

    3. What is the relationship between filaments and sigmoids that form in the cavity above filaments?

     

    Ø    Interactions Between New Active Regions (EFRs) and Pre-existing Filaments/Prominences:

    1. What physical processes seem to be involved in the interaction between EFRs and pre-existing filaments/prominences?

    2. Is there evidence that the birth of a new active region causes a disruption

    (slow rise, activation and/or eruption)?

    3. If there is a relationship between the birth of a new active region and the

    activation and/or eruption of a filament what is the relationship between the locations of the EFR and destabilized filament (distance from the EFR and the filament).

    4. Is active region rate of growth and/or sunspot area and count matter?

     

    Ø    Filament Channels in the Chromosphere:

    1. How do fibrils become aligned with the polarity boundary?

    2. What is the typical lifetime of fibrils in filament channels and how does it compare with the lifetimes of filament threads?

     

    Ø    Filament Formation – Spines:

    1. Does the initial mass in spine threads come from injection of chromospheric material into filament structures or by condensation or both?

    2. Is the time of formation of filament spines dependent on quantity and duration of canceling magnetic fields?

    3. Is there evidence of high speed flows in the spine related to network canceling fields?

     

    Ø    Filament Formation – Barbs:

          1. When new barbs form, is there evidence in the chromosphere or corona

           related reconnection takes place between spine threads and new sources

           of magnetic fields (intranetwork fields and/or ephemeral regions)?

           2. Are mass ejections detectable in relation to canceling fields at the

           footprints of barbs?

     

    Ø    Filament Formation – Arches:

    1. Are the arches that form at the base of  filaments/prominences barbs related to magnetic fields of supergranules? 

    2. Do the arches form at the base of spines as well as at the base of barbs?

    3. Do the downflows along arches terminate at sites of canceling magnetic

        fields or in areas of one polarity only?

    4. Does the interaction of downflowing threads produce waves in the arches

    that form at the base of these downflows?

    GBO OBSERVING PROGRAM

    On the basis of specific input from their planners, list each of the key GBOs, persons who are the point of contact, what their observations will do for the goals, and the specific observing/instrument setups they will run.

    SPACE MISSION OBSERVING PROGRAM

    On the basis of specific input from their planners, list each of the key spacecraft/instruments, persons who are the point of contact, what their observations will do for the goals, and the specific observing program they will run, (e.g., SOHO EIT: Barbara Thompson, images and spectra in various EUV wavebands for multithermal structure of flares, as defined by SOHO JOP 98.)

    TARGET

    The MM Chief Observer will choose a filament or prominence for this observing program when a filament/prominence displays one or more of the following:

     

    Ø    Active filament/prominence 

    Look for an expansion and/or darkening of a filament (brightening of a prominence). The darkening of a filament is best detected in slightly off-band (-0.50A) H-alpha images or H-alpha images obtained with broad-band H-alpha filters. Frequently the activation phase ends without entering an eruptive phase. If the active filament is located within an active region, it often precipitates a flare.

     

    Ø    Ascending (Eruptive) Disappearing Filament/Prominence

    Look for an old quiescent prominence located in a large decaying active region (often the active region is several rotations old).  The desired region target is decaying, sometimes only a plage remnant and almost always spotless, with a history of better than average flare activity in previous rotations. Observe carefully for any indication that the prominence is ascending slowly above the limb.  A filament on the disk often appears to be changing position as it rises.  The process takes several hours or even days before it disappears.  In some cases (rare), the filament disappearance is followed by a major two-ribbon flare located along the filament base.

     

    Ø    Filament Eruption Associated with the Occurrence of an Emerging Flux Region (EFR)

    A new bright rapidly growing active region often results in a filament to enter an active phase leading to an eruption.  There is a greatly increased chance if the filament is located within 20 heliographic degrees of the strong EFR.

     

    Ø    Filament Observing Targets not Associated with Active and/or Eruptive Phases 

    During periods of very quiet solar conditions, a filament target may be the only desirable target.

    1. Growth of a prominence at the limb or a filament against the disk.  Track

    the prominence or filament for as many days as possible.

    2. Track a prominence crossing the limb to observe its base along with its barbs and spines.

    3. Evolution of mini-filaments in ephemeral active regions on the quiet solar disk.

    The target position should be in a quiet portion within or close to the active region belt.

    4. Formation of a filament channel on the exterior boundary of a small new active region.  Track the target for several days until the channel forms and a filament is well developed.

    SCHEDULING CONSIDERATIONS

    List specific scheduling considerations (i.e., schedule this plan during a specific VLA observing run, wait for a certain target of opportunity, etc.)


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