Title: Solar Magnetism
1Solar Magnetism Activity(?????????)
- Jingxiu Wang
- National Astronomical Observatories
- Chinese Academy of Science
2 0. Long list of the discoveries
- 1843 Samuel Heinrich Schwabe 11-y sunspot
cycle - 1852 Edward Sabine geo-storms vary with sunspot
cycle - 1859 Richard C. Carrington Richard Hodgson
observe independently a solar flare in WL - 1908 Ellery Hale intense magnetic fields in
sunspots - 1919 Ellery Hale discover 22-y magnetic cycle
- 1949 Alfred H. Joy Milton L. Humason stellar
flares - 1950-9 John Paul Wild et al Type II Type III
radio bursts Andre Boischot Moving Type IV
burst - 1951-63 Herbert Friedman et al. intense X-ray
emission - 1960-1 Gail E. Moreton Moreton waves in
chromosphere - 1962-4 Charles P. Sonett interplanetary Shocks
- 1971-3 Richard Tousey 1974 John Thomas Gosling
CMEs
3Long list of the discoveries
- 1972-3 Edward L. Chupp et al. Gamma ray lines
in flare - 1981 Robert P. Lin et al. flare hard X-ray
source - 1980-9 George Doschek Ester Antonucci
chromospheric evaporation in flare - 1982 Russell A. Howard et al. Earth-directed
halo-CMEs - 1980-82 Edward L. Chupp et al. -- energetic
solar neutrons - 1990-5 Donald V. Reames two-class solar
energetic particles - 1992 Saku Tsuneta cusp geometry of soft X-ray
flares - 1994 Satoshi Masuda et al. loop top hard X-ray
source - 1997-8 Alphonse C. Sterling, B.J. Thompson N.
Gopalswamy et al. -- Coronal dimming and waves
4Key development of the theories
- 1946 Ronald G. Giovanelli idea of magnetic
reconnection - 1946 Thomas Gold Fred Hoyle flare theory in
the view of magnetic loop interaction - 1958 P.A. Sweet 1963 E.N. Parker slow
reconnection - 1964 Harry E. Petschek fast magnetic
reconnection - 1966-8 Peter Sturrock early standard flare
model - 1973-4 Yutaka Uchida theory of Moreton waves
- 1976 Tadashi Hirayama and 1978 Roger A. Kopp
Gerald W. Pneuman standard flare models for
two-ribbon flares - 1981-2001 Ronald L. Moore et al. --
tether-cutting model - 1993 P.A. Isenberg et al. flux rope catastrophe
model - 1998-9 K.S. Antiochos magnetic break-out CME
model
5Outline
- Overview of Solar Magnetism
- Measurements of Solar Vector Magnetic Field
- Studies Based on Vector Magnetic Field
Measurements - Flare-associated magnetic changes
- CME source regions and initiation
6Solar Atmosphere
Tachocline
7Solar activity
- Solar flares active region scale activity
- Coronal mass ejections large or global scale
activity (?) - Ubiquitous activity on the quiet Sun
small-scale activity - -network bright points (filigrees)
- -micro-flares
- -min-filament eruptions
- -X-ray bright points and X-ray jets
- -UV/EUV explosive events
- They are magnetic in nature, and powered by the
free magnetic energy, and controlled by the
structure and evolution of solar magnetic field
-
81. Overview of Solar Magnetism
- 1.1 Scientific Opportunities
- Solar magnetism and activity are one of the most
exciting and challenging disciplines in solar
physics and astrophysics - The magnetic Sun is a laboratory to the dynamic
behavior of cosmic magnetic fields. - A key for understanding and predicting the
impacts of the Sun on the Earths global changes
and space weather - A basis for understanding the only known system
in the Universe for the intelligent life been
created and flourishing
9Solar Effects on Life and Society
101.2 Morphology Classification of Solar Magnetic
Field
- 1.2.1 Active region field
- Sunspots strong field diagnosed by Hale (1908),
which marked the beginning of astrophysics - Plage enhanced magnetic network, bright areas
surrounding sunspots and in decayed active
regions - EFRs emerging flux region, the basic brick to
build solar active regions - MMFs moving magnetic feature, intriguing
properties of sunspot, and a puzzling phenomenon
11 At 0.2 arcsec Spatial resolution
Granule
Penumbra
?Umbra
?
Lightbridge
12?filament
?plage
?fibrils
13Plage how they come from decayed active region
and appear as enhanced network
Plage
Quiet
Enhanced
14- 1.2.2 Ubiquitous small-scale magnetic field on
the quiet Sun - Network magnetic field quiet magnetic network,
first defined from chromospheric observations
CaII k H? brightness pattern at the borders of
supergranulation. - Intranetwork magnetic field
- The weakest component of solar magnetism,
contributed 1024Mxd-1 flux to the Sun - Ephemeral (active) regions
- Small scale bipoles in both quiet and
active Sun . Hageneer (2001) estimated
5?1023Mxd-1 in the form of ephemeral regions
15- Hinode movie of an enhanced network area
161.3 Intrinsic Properties
- 1.3.1 Concept of strong elementary flux tubes
- Since the early of 1970s, an idea has been
widely accepted that more than 90 of Suns
magnetic flux is in the form of strong flux tubes
with field strength gt1kG, and diameter lt150 km.
Convective collapse is the known interpretation.
There has been debates on this the nature of
magnetic elements on the Sun strong or weak?
New facts and idea emerged in the middle of
1990s. - 1.3.2 Weak magnetic field on the Sun
- Several key works to re-activate this field
are Keller et al.(1994), Wang et al.(1995),
Lin(1995), indicating, indirectly or directly,
the weakness of IN fields.
17- Indeed, hints of a weak magnetic field
component that covers the entire Sun have
been discovered in several recent observations.
This global phenomenon may be of crucial
importance for the magnetic cycle and
variability. - --- Report from American
National Research Council (2001, p246)
18Importance of the Weak Field
- Significant amount of Sun flux is in the form
of intrinsically weak magnetic element. Totally
1024 Mx flux appeared to the Sun each day in the
form of intranetwork elements (Wang et al. 1995)
-- one order of magnitude larger than network,
two order of magnitude larger than ARs. - The interaction of IN and network fields may
provide enough energy to heat the corona and
accelerate the solar wind (Zhang et al.1998). - Theoretically, another type of solar dynamo may
operate in the solar surface layer.
191.4 Large-scale pattern
- 1.4.1 Active Complex (activity Nests)
- It consists of one or more large and complex
active regions, persists for several rotations,
(even years) by additional region forming as
earlier ones decay. The foci of super active
regions and major solar events. Stellar spots in
stellar astrophysics? - 1.4.2 Coronal hole
- An extended region of the corona with low
density and assciated with dominantly unipolar
phtospheric regions having open field topology.
They are the source of high-speed solar wind.
Coronal hole are darker in X-ray, but brighter in
HeI 10830Ã¥ images.
20? Coronal Hole
21Discovery of Polar kG field by Hinode
221.5 Two observed modes of magnetic field evolution
- 1.5.1 Flux emergence
- Emerging flux regions (EFRs) and Ephemeral
regions (ER) in the form of ? loops. - Moving magnetic features (MMFs) from the border
of sunspot -- in small bipole pairs? What they
are? - Intranetwork elements in cluster of mixed
polarities. - U-loop emergence? How about the subsurface
connection?
23Flux emergence in the form of ?-loops
- It should be understood why
- the appearance of new flux
- to solar surface is mostly
- in the form of ?-loops even
- for smallest ephemeral
- regions. Buoyancy instability?
- If we can simulate an active
- region from very beginning to
- the end of its life. How about
- magnetic fields in other stars?
-
?
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25- The newly emerging magnetic flux region (EFR)
plays a decisive role in almost all the forms of
solar activity. EFR seems the driver of solar
activity in most cases. To identify an EFR, to
reveal its manifestations, to find the physical
link of EFR to the energy storage and explosive
release appear to be a key task in both
observational and theoretical studies. Since the
first detection (Bruzek, 1967 Martres et al.,
1968 Zirin, 1972) EFR has been always a focus in
solar activity studies.
26- Is there U-loop emergence?
- Spruit et al. (1987) use this model to
interpret the magnetic flux cancellation and the
intra- network fields
271.5.2 Magnetic flux cancellation
- In 1985, magnetic flux cancellation was first
described by using high resolution Big Bear
magnetograms (Livi, Wang, Martin, 1995 Martin,
Livi, Wang, 1995 Wang, Zirin, Shi, 1995). By
definition, flux cancellation is the mutual flux
disappearance of closely spaced magnetic fields
of opposite polarities. It has been identified to
be the most important mode of flux disappearance
on the Sun. It is more likely the magnetic
reconnection in the lower solar atmosphere.
28Flux cancellation (magnetic reconnection in the
lower atmosphere) seen in AR9077
Spatially coincided but time- scales are clearly
different
Two-step recon. scenario
292. Measurements of Solar Magnetic Field
- 2.1 Zeeman Effect
- 2.2 Radiation Transfer of Stokes Parameters
- 2.3 Spectroscopic and Filter-based Measurements
302.1 Zeeman effect
31- 2. 2 Radiation Transfer of Stokes parameters
- For a single wave, we can decompose the harmonic
- vibration of the electric vector, E , propagating
along - the
z axis into its x and y -
components. For a full -
polarized wave, the four -
Stokes parameters are -
defined and used to -
describe the magnitude, -
orientation, and -
polarization degree. -
Stokes I is then defined - as
I (I,Q,U,V) -
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33Summary of key relations
?
?
34 2.3 Spectroscopic and Filter-based Measurements
- 2.3.1 Spectroscopic measurements, or Stokes
polarimetry - -- Use full spectral information of four
Stokes parameters to determine, at the same time,
the magnetic vector, and the thermal and dynamic
parameters of the magnetized plasma point by
point. - -- Basically an inversion or a non-linear
fit of Stokes parameter line profiles. - -- In principle, Hanle effect,
magneto-optical effect can be treated in a
consistent way.
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36Transfer equations for polarized radiation
- The transfer equations for polarized radiation
(Lites et al. 1988). I(I,Q,U,V) , z is the
position along the line of sight toward the
observer, is - the absorption matrix, and j is
the emission vector
- A simple solution is based on the assumption of
Milne-Eddington model atmosphere the source
function is described by a linear variation with
the optical depth, and the other physical
parameters, such as the field strength, field
inclination, field azimuth, Doppler shift,
Doppler width, ratio between line absorption and
continuum absorption, damping parameter,
macro-turbulent velocity, stray-light fraction,
and stray-light shift, are not changing with the
optical depth.
37Inversion
- Based on the solution of transfer equations for
polarized radiation, one obtains the best fit of
observed Stokes profiles by using the
least-squares algorithm, and considers the
physical parameters corresponding to the best
fitted profiles as the atmospheric parameters
forming the observed Stokes profile. - The merit function can be written
- .
-
-
- where the index i(1,2,,M) stands for
the wavelength samples, the indices obs and
syn refer to observed and fitted data,
respectively. The inversion technique is robust
when applied to stronger polarization signals
from active region.
38Average Unsigned BVapp 11.2 Mx cm-2 Noise
(1s) 3 Mx cm-2
39Polarization integrated in wavelength
- The wavelength-integrated circular and Linear
polarizations are defined as -
-
- One determines the calibration constant relating
Vtot to longitudinal field and relating Ltot to
transverse field by these pixels with the
stronger polarization signal in the quiet region.
40- 2.3.2 Filter-based measurements, or vector
magnetograph - -- Use narrow band birefringent filter to get
images of I, V, Q, U at line wing (or line
center for QU), then construct the Bx, By, and
Bz images immediately. - -- Only use partial information contained in
the four Stokes profiles. - -- The thermal and dynamic information of
magnetized plasma should be determined from
Dopplergrams or other diagnosis. - -- Hard to get idea on how strong the
magneto-optical effects would be.
41?o
Il-Ir??I/?????
?
?
2???2
An idea is that the transverse field is
related to the second order of derivatives of
intensity, therefore should be determined at the
line center since where there is the strongest
signals of the second order of derivatives. But
Jefferies et al.(1989) identified that this idea
was not deduced from accurate treatment.
42- Calibration of vector magnetograms is based on
the following formulas -
-
- where are calibration
coefficients for line-of-sight and transverse
components, respectively, and
43Some vector magnetographs
442.3.3 Comparison of two types of vector field
measurements
- The Stokes polarimetry provides the most accurate
measurements of the structural details of the
magnetic vector and plasma dynamics. But often
the temporal resolution and sensitivity are
lower, the field of view is often smaller too. - The filter-based measurements provide the
information on the vector field structure and
evolution, but may suffer from magneto-optical
effect, crosstalks of Q/U and V. The sensitivity
and temporal resolution are higher, and often the
field of view is larger. We can easily integrate
many thousands of vedio frames to enhance the
sensitivity.
453. Studies based on the observed vector
magnetograms
- 3.1 Magnetic connectivity
- 3.2 Magnetic shear (magnetic non-potentiality)
- 3.3 Electric currents
- 3.4 Magnetic helicity (magnetic complexity)
- 3.5 Topology peculiarity
- 3.6 Theoretical extrapolatio
463.1 Magnetic connectivity
- For the observed bipole which
configuration is correct ?
In an observed line-of-sight magnetogram
?
Interface
?
?
?-loop
?
?
Knotted Loop
?
-
-
U-loop
O-loop
-
-
?
?
47Two canceling fields are not connected by
magnetic lines in transverse magnetogram
?
?
483.2 Magnetic shear
- 3.2.1 Definition
- Magnetic shear is a measure of the deviation of
observed transverse field from the potential
configuration - . Hagyard et al.(1984) first
suggested to use shear angle defined as
to quantitatively desribe the
shear degrees. ? is field azimuth. - Magnetic free energy is defined as
- In more complicated cases, the minimum
energy status is not that of potential
configuration. -
49Example in the original work of Hagyard et al.
50- Hagyards shear angle (1984)
- LÜ et al.(1993) suggested a vector shear angle
-
Where, - It was suggested to be the only physically
correct definition of shear angle. For a
force-free field,
Bo
Bp
??
??
Bot
Bpt
51Two modes of shear development
- Theoreticians think that the magnetic
- shear is caused by shear motion of
- two footpoints of a single loop, but
- obsevers say NO ! For a force free
- field
-
from Wang(1994)
?
?
Emergence mode ?
? Generation mode
? Shear emergence
Rotation of the B??
52Evolution of the sheared core in X-rays (Su et
al. 2007)
Hinode observation of shear development
XRT observations of sheared field formation From
0019 UT on Dec 10 To 1243 UT on Dec 12
SOT observations Emerging flux West-to-east
Motion in the Lower sunspot (Kubo et al., 2007)
533.3 Electric Currents
- Only the vertical currents can be deduced from
the transverse components of B vector - In the Fourier domain
54- In AR 6233 for a few flares (Wang et al. 1996)
55Quiet Sun magnetic fields are non-potential
563.4 Magnetic Helicity
- 3.4.1 Helicity and topology constraint on energy
status - Helicity is a measure of magnetic complexity,
helicity density is defined as - When , the minimum energy
status is Bpotential - When , the minimum energy
status is Bcons-fff - that is
- When the connectivity is conserved, the minimum
energy status is non-linear force-free field - When all the magnetic lines of force is rooted
in the photosphere, the maximum energy status is
the open field, this is called as Aly
Sturrock constraint
57- 3.4.2 Helicity in active regions
- For an solar active region which has an open
boundary, the photosphere, the helicity is not
conserved. Its evolution is determined by three
physical processes (Wang, 1996) - The cross helicity plays the decisive
role surface dissipation contributes 10-3, while
the dissipation from current helicity is
ignorable, 10-7.
58- It is more interesting to see the different trend
of current helicity and line-of-sight flux.
?
59 3.5 Topology peculiarity 2D Magnetic
singular point
- If we can derive the peculiarity from
observations? - Poincare number by
- Wang Wang (1995)
-
60Zhao et al. (2005,2007)
613D null pointsin AR 10720
623D magnetic skeleton Associated with spiral
magnetic null ?
634. Flare-associated magnetic changes
- Gradual pre-flare evolution
- Rapid magnetic changes in the course of flares
- Flare-induced signals in polarization
64Magnetic changes observed by Hinode at the
spatial resoultion of 200km
65Three inter-connected issues
- 4.1 Pre-flare magnetic configuration and
evolution - 4.2 Rapid magnetic changes in the course of
flares - 4.3 Flare-induced signals in polarization
measurements - The importance of these studies is to examine our
physical understanding on the flare phenomenon
which takes place in a wide range of
astrophys-ical subjects.
664.1 Pre-flare state (What we know by 2000 ?)
- Strongly curved magnetic neutral lines, e.g., in
S shaped or reverse S shaped (Somov 1985) - Steep gradient of line-of-sight fields, say
several hundred G per kilometer (Wang Li 1998) - Filament activation -- darkening, bifurcating
twisting (Ramsey Smith 1963 Rust et al. 1994) - Emerging flux regions (EFR) (Bruzeck 1967 Zirin
1972 ), particularly within great d-sunspots
(Zirin 1988 ), or in an activity center of active
regions (Bumba 1986) - Highly sheared transverse fields (Hagyard et al.
1984 Lü et al. 1993) - Magnetic flux cancellation (Livi, Wang, Martin
1985 Martin, Livi, Wang 1985) - Current concentration (Moreton and Severny 1968
Lin Gaizauskas, 1987 Ding et al. 1987)
67Pre-flare State (Whats later attention?)
- Helicity injection introduced into flare and
active region studies (Wang 1996 Pevtsov et al.
1996 Bao et al. 1999 Moon et al. 2002a,b
LaBonte et al. 2007) Relevant theoretical flare
model proposed (Kusano et al. 2003). - New attentions on sunspot dynamics in driving (or
triggering) flares based on more detailed
observations (Hiremath et al. 2005 Tian
Alexander 2006 Zhang et al. 2007, 2008). - Flare productivity based on systematic data-base
and large sample(Cui et al. 2006, 2007)
68Pre-flare State (More recent efforts)
- Discriminant Analysis of flaring flare-quiet
ARs (Leka Bernas,2003a,b, 2006, 007), Falconer
et al (2001, 2003, 2006)
- Search for synthesized or effective parameter
(Schrijver 2007 Georgoulis Rust 2007 Regnier
Priest 2007) - Effective-connected fields Beff ??(Fi,j /
L2i,j) - gt1600, 2100 G for M, X class flares at 95
probability - Unsign flux within 15 Mm to neutral line gt
2X1021Mx for major flares
694.2 Rapid magnetic changes in the course of
flares (distinction?)
- First reported by Patterson and Zirin (1981) in
term of flare-transient. It is soon recognized
that the flare transient is not real magnetic
change but produced by transient emission of the
line for getting magnetograms (Patterson 1984). - Distinction between magnetic transient and
magnetic changes in the course of flares can be
drawn by the facts (1) recover or not in
magnetograms after the flare impulsive phase? (2)
associate with the sites of particle
precipitation ?
70Rapid magnetic changes in the course of flares
(reports in 1999-2008)
- 29 X-class 5 M-class flares
- 24 events with line-of-sight magnetograms
presented magnetic flux changes - 9 with vector magnetograms showed horizontal
field and shear increase during flares - 13 flares with white-light images presented
sunspot umbra and penumbra changes - Most with halo-CMEs
71Rapid magnetic changes in the course of flares
(key facts?)
- All are referring to major flares. (see Sudol
Harvey 2005 ). - The magnetic changes are abrupt, persistent, and
significant in both longitudinal and horizontal
fields - Magnetic flux is in order of 1 - 6 times of 1020
Mx (Wang et al. 2002, Meunier kosovichev 2003) - Flux density is from 30 to over 200 G (Kosovichev
Zharkova 1999, 2001 Sudol Harvay 2007). - Horizontal changes diagnosed from limb events
(Cameron Sammis 1999 61 Spirock, Yurchyshyn,
and Wang 2002) and disk observations (Liu et al.
2005 Wang et al. 2002, 2004 Chen et al.2007).
72Rapid magnetic changes in the course of flares
(key facts?)
- Rapid penumbra decay in the outer d-spot
structures and the enhancement of inner penumbra
and central umbra are a remarkable fact uncovered
by Big Bear group (Wang et al. 2004, 2005 Liu et
al. 2005 Deng et al. 2005 Chen et al. 2007). - Penumbral decay seems more related to horizontal
magnetic changes.
73Example from Sudol Harvey (2005) Why those
parts but not other sites changed?
74Before Flare After Flare
Example from Haimin Wang et al. (2002a) what
caused the rapid enhancement of B? shear ?
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76Why study magnetic changes during flare in the
photosphere?
- An aspect has not been confronted by all flare
models and most theoreticians - Key facts in understanding flare physics, in
particular, the triggering of major flares - Only a few events were studied based on observed
vector magnetograms, and largely improved
observations of vector fields available now
77A basic assumption of flare models (Priest
Forbes 2002)
- For a given component (Bn) of the magnetic field
at the - solar surface, the magnetic energy in the
- overlying corona is a minimum when j 0.
- But Bn is observed not to change significantly
- during a large flare, and so the free energy
for the - flare comes from distortions of the magnetic
field away - from a current-free (or potential) state. In
other words, - the magnetic field before a flare can be
written as - B Bph Bcor, where Bph arises from
photospheric - or sub-photospheric currents and is invariant
during a - flare, whereas Bcor arises from large-scale
coronal - currents and is the sourceof the flare energy.
- (Ann. Rev. A
Ap. 10, 313-377, 2002)
78Overall view of flare models
79An examination with majore flare on January 20
2005?
- A flare of X7.1 class, which took place from
0626-0726 UT - Hardest energetic proton event with the highest
100 MeV proton flux since 1989 - Followed by Earth-directed CME at speed about 882
km s-1 with clear acceleration - Coverage of vector magnetograms with adequate
cadence and sensitivity at HSOS
80Vector magnetograms of AR10720
81(No Transcript)
82AR 10720 at N12W58
83- Difference magnetograms of
- 0731 0616 UT
? B?
? B??
WL
155nm
84(No Transcript)
85- Time-sequence of TRACE 155 nm images
86- SOHO/EIT images Expansion speed of outer loops
1, 6, 70 km/s, respectively
6.3 km/s
1.3 km/s
73.0 km/s
87Vector magnetograms in heliographic coordination
system
? B?
? B??
88- Free magnetic energy density distribution
0616
89Summary of the observations
- A rapid, significant enhancement of horizontal
magnetic fields in an extended area centralized
on the magnetic neutral line and reduction in the
sunspot outskirts - The rapid enhancement is likely caused by an
impulsively fast growth of a sheared EFR - The enhanced horizontal fields are co-spatial
with a lower-lying flux rope - The lower-lying rope remains in position, while
the outer EUV loops erupted impulsively
90Implication to flare magnetism
- No any flare model has predicted such rapid
changes in horizontal magnetic fields in the
photosphere during flares. Each model, say
standard model (since 1960s 80s), two-step
reconnection (Wang Shi 1993), tether cutting
(Moore et al. 1980s-2001), EFR-triggering (Chen
Shibata 2000), magnetic breakout (Antiochos 1998)
, seems to only be correct in one or some aspect
of the physics of flare energy built-up and
explosive release - A set of lower-lying ropes and their associated
horizontal fields seem to play a decisive role in
triggering the flare in some catastrophic manner
91A suggested scenario
- Rapidly growing core flux rope results in a MHD
catastrophe of magnetic reconnection, formation
eruption of higher flux rope for flare/CME
924.3 Flare-induced signals in polarization
measurements
- The flare-induced signal in the form of polarity
reversal in circular polarization, mostly in
sunspot penumbrae, and recovers soon after the
flare impulsive phase. - Impact linear polarization of the Ha (Henoux et
al. 1990), EUV (Henoux et al. 1983), and X-ray
(Haug 1981) emissions in flare ribbons resulted
from the collisional excitation by beams of
charged particles electrons or ions
93Flare in AR 10720on Jan.15
945. CME source regions initiation
- 5.1 Outstanding questions about CMEs
- 5.2 Trans-equatorial solar activity
- 5.3 Large-scale nature of the source regions
- -- classification
- -- global magnetic activity
- -- coupling of flare and trans-equatorial
activity - -- simultaneous flux emergence
- 5.4 Processes leading to CME initiation
- -- flux cancellation
- -- helicity annihilation
- -- sunspot dynamics
95 5.1 Outstanding Questions on CMEs
- Physics of CME initiation signatures?
- What determine when, where how fast of CMEs?
- CME large-scale magnetic structure?
- CMEs long-term magnetic field evolution?
- Role of magnetic reconnection in CMEs?
- Role of magnetic helicity?
- CME flare, filament eruption?
- CME magnetic clouds (or ICME)?
- Why and what determine geo-effectiveness?
- Role Cyclic behaviour of CMEs?
- Mass ejection in stars galaxies?
965.2 Trans-equatorial solar activity
Trans-equatorial Loops Filaments in Sun-Earth
connection events on November 2004
97- In the Sun-Earth Connection events of November
2004, we found that solar flares in AR 10696 are
often associated with large-scale
trans-equatorial activity (TA) in the forms of - the formation and eruption of trans-equatorial
loops (TELs) - the formation and eruption of trans-equatorial
filaments (TEFs) - the trans-equatorial brightening (TEB) beneath a
trans-equatorial halo CME - Only those flares that associated with TA are
CME-associated.
98- Magnetic configuration for the TELs and TEFs
- TELs connecting opposite polarity flux of AR695
695 ( a coroanal hole) on both hemispheres - TEFs laying above the large-scale
trans-equatorial magnetic neutral lines
99- Brief notes
- Prominence (filament) flare were first detected
in the 19-th century - Trans-equatorial magnetic loop (TLs) was
predicted by Babcock in 1961 - TLs were first detected by Skylab X-ray
observations in 1973 Their correlation to CMEs
was established by Khan Hudson (2000), Glover
et al.(2003), Zhou et al. (2006) - Trans-equatorial filament (TFs) was first
described by Wang (2002), and its role in CMEs
were discussed by Wang et al.(2005, 2006), Zhou
et al.(2006)
100- Trans-equatorial filament and its eruption
101- Formation eruption of TFs
CME
1026-7 November 2004 event
Related to filament eruptionand
trans-equatorialarcade
dominant electron flux
103An example from Bastille Day flare/CME Event
1045.3 Large-scale nature of the source regions
5.3.1CME????????
C1, ???????(EBR)
C2, ?????
C3, ?????
C4, EBR???????
(Zhou, Wang, and Zhang, 2006)
105Extended Bipolar Regions seem to play a decisive
role in CME process
106CME productivity
107Nanchy Redioheliograph observations By (Yayuan
Wen et al. 2006)
1085.3.2 Global magnetic connectivity in CMEs
Magnetic connectivity with the CME on Oct.
28 2003 (Zhang et al. 2007)
109- Key topologic connectivity Patterns in some
global flare/CMEs
Oct. 28, 2003
1105.3.3 Coupling of trans-equatorial activity with
flares in AR
- It was noticed that one or several major flares
in the AR are followed by an increase of
brightness and non-potentiality of a TEL. - These coupled events, have a lifetime of more
than 12 hours. - Their associated halo CMEs always have positive
acceleration, indicating prolonged magnetic
reconnections in the outer corona at high
altitudes.
111Halo CMEs
112- Coupling of flare in AR and trans-equatorial loos
TELlight curve
CMEs
113Further Physics
What causes the formation of TLs and what makes
the TLs sheared, flared and Finally erupted
Why a CME associated with growth of TEL
accelerated that associated with TEL eruption,
decelerated ?
114Brightness
Temperature
115A scenario for TEL CME
116A statistics of CMEs associated with
trans-equatorial activity
1175.3.4 Quasi-simultaneous Flux Emergence (Zhou,
Wang, and Zhang, 2007 )
118(No Transcript)
1195.4 Processes leading to CME initiation
- 5.4.1 Flux cancellation magnetic reconnection
in the lower solar atmosphere
Example for Bastille Day event on July 14 2000
120Flux emergence and cancellation in homologous
CMEs initiated form AR 9236
1215.4.2 Helicity annihilation
- CMEs are suggested to originate from the over
accumulation of magnetic helicity (Rust Kumar
1994 Low, 1996). But where helicity comes from? - Recent studies (Chae et al. 2001 Demoulin et al.
2002a, 2002b Green et al. 2002 Kusano et al.
2002 Moon et al. 2002 Nindos Zhang 2002
Nindos et al. 2003 Pevtsov et al. 2003) have
revealed the inability of AR fields to create
enough helicity
122- This inability of ARs arouses a question whether
or not the above approaches are fully reasonable?
What is the source of magnetic helicity in CMEs? - We tried, on the other hand, to examine whether
particular helicity patterns are retained by
CME-associated ARs. We focus on the helicity
distribution and examine whether the helicity
patterns support the known CME models.
123- Contrary to the helicity-charging picture (Rust
and Kumer 1994), we find evidence that the newly
emerging flux often brings up helicity with a
sign opposite to the dominant helicity of the AR.
- Moreover, the flare/CME initiation site is
characterized by close contact with magnetic flux
of the opposite helicity coinciding with observed
flux cancellation.
124Current
Helicity
125 126- If flare/CME initiation results from magnetic
flux cancellation (Zhang et al. 2001a, 2001b),
then the opposite polarity flux in the
cancellation also generally has opposite
helicity. - This suggests that the flare/CME initiation
originates from the interaction of topologi-cally
independent flux systems. Each flux system in the
interaction has its own distinct chirality.
Thusly, some type of topological collapse or
degeneration must be involved in the flare/CME
triggering processes.
1275.4.3 Sunspot dynamics rapid rotation
128- Rotation of sunspot penumbra (Zhang, Li,
Song, 2007, ApJL)
129 130 0. General remarks
- The complexities of the Sun its internal
structure, rotation and convection, and the
resulting cyclic and random generation of its
magnetic fields and the magnto-active, hot,
explosive, extended solar atmosphere and solar
wind are fascinating and challenging. Solar
magnetism and activity are a field that deserves
your energy and enthusiasm. -
1310. General remarks
- Pay more attention to observations
- Be critical to the well-known models
- Trying hard to not widen but narrow the gaps
between theories and observations. Without the
knowledge of Suns vector magnetic fields, we
have no way to understand the physics of solar
activity - Trying hard to see new physics. When the
mathematics becomes too much complicated it seems
time to stop to find new physics when the
observation goes into too many details it seems
time to stop to think whats the physics we are
working for
132- Thank you for your patience
- Wish you a great progress in your studies