Topics II
Large Scale Explosions & Eruption
flares, CME, and space weather
Sub-group of NGSPM teamDavid E. McKenzie
Lyndsay Fletcher
Toshifumi Shimizu
Kanya Kusano

Key scientific objectives
Key observations
Instrument requirements

Sub-objectives
1.

2.

3.

4.

5.

6.

Measure the energy build-up processes inflaring and CME regions
Identify the trigger mechanism of solar
flares and CMEs
Clarify the mechanisms of destabilizing anderupting of the entire system
Understand the processes of fast magnetic
reconnection
Understand the formation mechanism ofdelta sunspot
Understand the particle acceleration

II：Mechanism of large-scale solar eruptions andalgorithm for prediction
Sub-objectives

Tasks

Key Observations

Requirements

Instruments

Measure theenergy build-up
processes in flaring
and CME regions

II-1-1: Measure electric
current configuration
reaching corona below
from photospheric andchromospheric magnetic
fields, and evolution ofmagnetic free energy

・Vector magnetic fields
in photosphere andchromosphere・Wide FOV covering AR・Continuous observation
for more than severaldays
・Data storage of large
number of ARs
・Vector magnetic fields
of dark filament
・Wide FOV time-series
photospheric vector
magnetic fields

Spectro-polarimetrye ~ 3x10-4
dx ~ 0.3” ,FOV > 300”
T: 5000 ~ 104K
dt < 10min,Time span ~ 1week

SOLARC/SUVIT
ASOTSpectro-polarimetrye ~ 3x10-4
dx ~ 0.3” , FOV >300”
T: 5000 ~ 104K
dt < 10min, Timespan ~ 1week
Spectro-polarimetrye ~ 3x10-4
dx ~ 0.3” , FOV >300”
T: 5000 ~ 104K
dt < 10min, Timespan ~ 1week
Total data period >1 year (for > 50events)

SOLARC/SUVIT
ASOT

II-1II-1-2: Measuredevelopment of magnetic
structure of dark filament(prominence on disk) untileruption

II-2

Identify the trigger II-2-1: Observe plasmamechanism of solar motions and fine magnetic
flares and CMEs
structures interacting withsurrounding fields before
flare occurrence, andidentify a key process tocontrol the trigger in the
majority of flares andCMEs.

・Vector magnetic andvelocity fields inphotosphere andchromosphere
・FOV covering AR・Data storage of large
number of events

SOLARC/SUVITASOT1. Measure the energy build-up

NLFFF extrapolation
DeRosa et al. 2015 ApJ
THE INFLUENCE OF SPATIAL RESOLUTION ON
NONLINEAR FORCE-FREE MODELING• NLFFF modeling results depend quantitatively on
the spatial resolution of the input boundary data,
and that using more highly resolved boundary data
yields more self-consistent results. The freeenergies of the resulting solutions generally trend
higher with increasing resolution, while relative
magnetic helicity values vary significantly between
resolutions for all methods.
• The solutions produced by the various methods
are significantly different at each resolution levelMeasurement of Poynting Flux

Measurement of Poynting Flux & Helicity Flux
Test of velocity inversion (Welsch et al. 2007)

II：Mechanism of large-scale solar eruptions andalgorithm for prediction
Sub-objectives

Tasks

Key Observations

Requirements

Instruments

Measure theenergy build-up
processes in flaring
and CME regions

II-1-1: Measure electric
current configuration
reaching corona below
from photospheric andchromospheric magnetic
fields, and evolution ofmagnetic free energy

・Vector magnetic fields
in photosphere andchromosphere・Wide FOV covering AR・Continuous observationfor more than several
days
・Data storage of large
number of ARs
・Vector magnetic fields
of dark filament
・Wide FOV time-series
photospheric vector
magnetic fields

Spectro-polarimetrye ~ 3x10-4
dx ~ 0.3” , FOV >300”
T: 5000 ~ 104K
dt < 10min, Timespan ~ 1week

SOLARC/SUVIT
ASOTSpectro-polarimetrye ~ 3x10-4
dx ~ 0.3” , FOV >300”
T: 5000 ~ 104K
dt < 10min, Timespan ~ 1week
Spectro-polarimetrye ~ 3x10-4
dx ~ 0.3” , FOV >300”
T: 5000 ~ 104K
dt < 10min, Timespan ~ 1week
Total data period >1 year (for > 50events)

SOLARC/SUVIT
ASOT

II-1
II-1-2: Measuredevelopment of magnetic
structure of dark filament(prominence on disk) untileruption

II-2

Identify the trigger II-2-1: Observe plasmamechanism of solar motions and fine magnetic
flares and CMEs
structures interacting withsurrounding fields before
flare occurrence, andidentify a key process tocontrol the trigger in the
majority of flares andCMEs.

・Vector magnetic andvelocity fields inphotosphere andchromosphere
・FOV covering AR・Data storage of large
number of events

SOLARC/SUVIT
ASOTMeasurement of Flare Trigger
Helicity cancellation(Reversed-shear)

Flare Ribbon

Bamba’s talk (O7A25)

Change in Bh

Wang 1992, Wang et al. 1994
Wang et al. 2012

AR11158

MHD Simulation

Opposite polarity

Kusano & Itahashi (to be submitted)

AR11158

Helicity cancellation

AR10930

Opposite polarity

time 9Jing et al. 2016 Nature
Unprecedented Fine
Structure of a Solar
Flare Revealed by the
1.6 m New Solar
TelescopeHigh cadence &High resolution

II：Mechanism of large-scale solar eruptions
and algorithm for prediction
Sub-objectives

II-3Tasks

Clarify theII-3-1: Identify MHD
mechanisms ofinstability mode bydestabilizing and observing dynamical
erupting of thechanges of coronalentire system
structure and electric
current system

Key Observations

Requirements

・High-resolution
coronal images,
velocity fields
covering AR・Time cadence totrack erupting
process
・photospheric vector
magnetic fields andmorphologicalchanges ofchromosphericthread structures

Spectropolarimetry e ~3x10-4dx ~ 0.3” , FOV> 300”
T: 5000 ~5×106K
dt < 20sec, Timespan ~ 1week

InstrumentsSOLAR-C
ASOT+coroanWhich Instability?
Stability of Torus Plasama
n=0 mode(Shafranov 1966)

Torus Instability(Kliem, Titov, Torok 2003)

𝑟𝑟 𝜕𝜕𝐵𝐵𝑧𝑧 3
𝑛𝑛 = −>
𝐵𝐵𝑧𝑧 𝜕𝜕𝑟𝑟2
decay index

Kink Instability

Double-arc Instability

Which instability ?
Chen et al. 2014 ApJ

Ishiguro & Kusano (to be submitted)

320km/s
25min
t0~500s
V0~80km/s

II：Mechanism of large-scale solar eruptions and algorithm
for prediction
Sub-objectives

Tasks

Key Observations

Requirements

Instruments

Understand theprocesses of fastmagnetic
reconnection

II-4-1: Observe discontinuity ofchromospheric magnetic fields(current sheets)

・Vector magnetic fields of upper
photosphere ~ chromosphere

SOLARC/SUVIT

Clarify relations between thereconnection rate and the guidefield in the solar chromosphereand the corona

・High-resolution coronal images,
velocity fields
・Chromospheric image withchromospheric vector magnetic field・Coronal vector magnetic fieldmeasured by Zeeman and Hanle
effect or extrapolated fromchromospheric and photosphericmagnetic field
・FOV covering AR・Images and velocity fields resolving
elementary structures in corona at
multiple temperatures (105~5×106K)
・Time cadence capable of tracking
fast motions of plasma
・Photometric accuracy capable ofdetecting faint structure

Spectropolarimetry e ~3x10-4dx ~ 0.3” , FOV >300”
T: 5000 ~ 104K
dt < 20sec, Timespan ~ 24hr
Spectropolarimetry e ~3x10-4dx ~ 0.3” , FOV >300”
T: 5000 ~5×106K
dt < ？sec, Timespan ~ 1week

II-4

II-4-2: Observe growing process
and motion of plasmoids incurrent sheets that could drive
the fast magnetic reconnection
II-4-3: Observe discontinuousstructuresof densityandtemperature associated withcoronal magnetic reconnection
and verify relations of shockwaves and plasma heating

SOLAR-C
ASOT+corona
DKISTdx ~ 0.3” , FOV > SOLAR300”
C?EUVST&HCI
T: 5000 ~5×106K
Dt < 20sec, Timespan ~ 1week

Fast Magnetic Reconnection
What determines the reconnection rate?


M~10－2±1≫S-P theory （S-1/2～10-7）

What is the role of plasmoids.

(Takasao et al. 2012)
Imaging~3”

Shibayama, Kusano, et al. 2015
sporadic small-scale Petschek-typeshocks

II：Mechanism of large-scale solar eruptions
and algorithm for prediction
Sub-objectives

Tasks

Key Observations

Understand theII-5

formationmechanism ofdelta sunspot
Understand the・Stokes profiles inparticle

chromospheric lines

acceleration

・Continuum
spectrum including

II-6

Balmer jump
・Radio burst
・Gyro-synchrotron
radiation
・Hard X-ray, γ-ray

Requirements

Instruments