REGION LIKELY TO PRODUCE GREAT FLARES

MAX MILLENNIUM COORDINATED OBSERVING PLAN 018

Scientific Goals | Ground Based Observatories | Space Based Observatories | Target | Scheduling Considerations

TITLE:	REGION LIKELY TO PRODUCE GREAT FLARES
AUTHOR:	Richard Canfield (canfield@physics.montana.edu) Montana State University William Marquette (wmarquette25@gmail.com) Helio Research
VERSION:	Version 6: 26 February 2015
SUMMARY:	This plan describes context and flare observations from ground-based and space-based instruments and observatories appropriate to solar active regions that are likely to produce (1) flares with either nuclear-line or high-energy gamma-ray emission that extends above 50 MeV, which are typically of GOES X (and high M) class, and are associated with fast and wide CMEs, or (2) very large flares, with GOES classification > X5, with or without such gamma-ray emission. This plan describes the circumstances under which the Max Millennium Chief Observer will declare a Great Flare Watch. Goal: To obtain multi-wavelength imaging and spectroscopic observations before, during and after gamma-ray solar flares, which will be the source of the most valuable and unique spectra and images from RHESSI. Approach: In a manner appropriate to each instrument, observatory, and spacecraft, to observe, if at all possible, the active region identified in the Great Flare Watch message from the Max Millennium Chief Observer distributed to the Max Millennium Message of the Day list.

SCIENTIFIC GOALS

The scientific goal of this program is to understand energy release, particle acceleration, and particle and energy transport in those flares that produce gamma-ray lines. Key questions are:

What is the partition of energy between ions and electrons?
Where are ions accelerated, and what are the physical conditions (temperature, density, velocity and magnetic fields) there?
What are the abundances of accelerated particles and the ambient atmosphere at the Sun?
What mechanisms accelerate both electrons and ions to high energies so rapidly and efficiently?
What mechanisms transport high-energy ions away from the acceleration site?
What are the characteristic signatures of flares that have potentially hazardous radiation effects?
What is the relationship between ion acceleration and CMEs?

Co-temporal data from ground and space-based observatories are crucial to answering these questions.

GROUND BASED OBSERVATORIES

SPACE BASED OBSERVATORIES

TARGET

The MM Chief Observer will choose an active region for this observing program when either of the following criterion is met:

Active region has produced a flare that is large (typically GOES X-class) and is associated with Fermi LAT nuclear-line or high-energy gamma-ray emission, typically with a fast and broad CME (if a region produced one such flare, it will probably produce at least one more).
Active region has an area > 1000 micro-hemispheres and is classified "beta-gamma-delta", and in addition has an "Island Delta" sunspot configuration with the following properties, of which the first three are most important:

Within the common penumbra there is dominant umbra, usually of p polarity, two or more surrounding umbrae of opposite polarity, and additional surrounding umbrae of p polarity.
The polarity structure is typically inverted, i.e., the westernmost umbra is f polarity.
The umbrae making up the configuration emerge together, i.e., the configuration does not form by merging or successive emergence of separate bipoles.
The common penumbra is surrounded by weaker flux whose polarity is opposite that of the dominant umbra. The weaker flux is typically the residual of a previous AR.

SCHEDULING

This is a target-of-opportunity plan. It will be called only when there is a region on the disk or the limb that is likely to produce a great flare, according to the criterion above.