By Valbona Hasandjekaj, Marta Kheyfets and Carol Bowen CBSE 7204 – Spring 2014.
CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division,...
-
Upload
felicity-manton -
Category
Documents
-
view
214 -
download
0
Transcript of CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division,...
![Page 1: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/1.jpg)
CME Eruption at the Sun and Ejecta Magnetic
Field at 1 AU
Valbona Kunkel
Solar Physics Division, Naval Research Laboratory
Collaborator: J. Chen
April 15 2013 12th Annual International Astrophysics Conference
![Page 2: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/2.jpg)
NRL Solar Physics Division
Hundhausen (1999)
“MAGNETIC FORCES”: MAGNETIC GEOMETRY OF CMEs
3D Geometry of CMEs–3 Part Morphology
Illing and Hundhausen (1986) Chen et al (1997)SOHO
• Dominant consensus from the 1980s and1990s (SMM era): CMEs are dome-like structures with rotational symmetry, not a thin flux rope Neither of the above
SMM
![Page 3: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/3.jpg)
NRL Solar Physics Division
INTRODUCTION: CME-FLARE PHYSICS
Key Questions in Coronal Mass Ejection (CME) Physics and New Answers:
• What forces drive CMEs?—evolution of a CME and its B field from the Sun (to 1 AU)
• What is the physical connection between CMEs and associated flares?
• What is the energy source? Open physics issues—quantified
A Physical Model of CMEs:
• The Erupting Flux Rope (EFR) model of CMEs: a quantitative theoretical model
that correctly replicates observed CME dynamics—direct comparison with data:
– CME position-time data from the Sun to 1 AU (STEREO)
– in situ B(t) and plasma measurements of CME ejecta at 1 AU (STEREO, ACE)
– CME data and associated flare (GOES) X-ray (SXR) data (near-Sun processes)
Theme of This Talk:
• What extractable physical information do data contain? Theory-data comparison at
both ends of the Sun-Earth region and the intervening CME trajectory.
![Page 4: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/4.jpg)
NRL Solar Physics Division
THEORY-DATA RELATIONSHIP
Physics Models: Characteristic Physical Scales
• MHD is scale invariant—models are distinguished by characteristic scales
• The EFR model---defined by MHD equations for macroscopic flux-rope dynamics
• What determines the flux-rope motion?---3D flux-rope geometry and physical scales
‒ Lorentz hoop force:
‒ A 3D plasma structure: and evolve
‒ Stationary footpoints: Sf = const and
• Initial equilibrium conditions:
B0, MT0 Acceleration time scale (Alfvenic)
• How are these scales manifested in the data?
2 2 2 2/ 0, / 0d Z dt d a dt
Sf
R
a
2 2( ) / ( ) / ( ) ln(8 / ) / 2 / /p p c pdV t dt t L t R a R a B B
2 2/ ( , , )a t pd a dt F B B p
2 2( ) / 4 / 2 ( )fR t Z S Z t
( ) ln 8 /L t R R a
![Page 5: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/5.jpg)
NRL Solar Physics Division
Dynamical Scales
Sf -SCALING OF FLUX-ROPE ACCELERATION
Chen, Marque, Vourlidas, Krall, and Schuck (2006)
22
2 ln (8 / )f
f
Sd Z
R R adt
Sf – Scaling
A geometrical effect – a flux rope at t = 0 and accelerated by the Lorentz hoop force
Directly manifested in data—3D geometrical effect/ /R Ap paR V R B
![Page 6: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/6.jpg)
NRL Solar Physics Division
PHYSICAL INFORMATION IN DATA: Best-Fit Solutions
• Extract physical information from observations—constrain the model by only the
observed height-time data, Zdata(ti), and calculate the best-fit solution, Zth(ti)
‒ Minimize the average deviation from the data (maximize the goodness of fit)
‒ data, model solution, and uncertainty at the i-th observing time
• Adjust Sf and to minimize D
‒ A “shooting” method
‒ Sf and calculated by the best-fit solution are the physical predictions of
the EFR model constrained by the height-time data
• The best-fit solutions can produce other physical predictions that can be tested
‒ Hypothesis:
1
| ( ) ( ) |1 Ndata i th i
ii
Z t Z tD
T Z
( ), ( ),data i th i iZ t Z t Z
( ) /pd t dt
( ) /pd t dt
( ) (1/ ) ( ) /pemf t c d t dt ( ) ( )SXRemf t I t
![Page 7: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/7.jpg)
NRL Solar Physics Division
INITIAL-VALUE SOLUTIONS
Input Parameters
• Model corona—specified and unchanged
‒ pc(Z), nc(Z), Bc(Z), Vsw(Z), Cd ,
• Observational constraints
‒ Sf, Zdata(ti), ISXR(t)
Model Outputs
• Initial field and mass—calculated, intrinsic
‒ Initial equilibrium conditions B0, Mt0, p0
• Initial-value solution
‒ Sf, “shooting parameter”
‒ Minimize D Sf, are physical predictions
Sf
p
Z
( ) /pd t dt
( ) /pd t dt
1.18
![Page 8: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/8.jpg)
NRL Solar Physics Division
EMF: CME-FLARE CONNECTION
D = 1.3% Z0 = 2.5 x 105 km Sf = 4.25 x 105 km <E>max = 3.7 V/cm
X
1
| ( ) ( ) |1 Ndata i th i
ii
Z t Z tD
T Z
![Page 9: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/9.jpg)
NRL Solar Physics Division
EMF: CME-FLARE CONNECTION
• Best-fit and good-fit solutions yield in close agreement with X-ray light curve.
• Predicted Sf is consistent with observation.
D = 1.3% Z0 = 2.5 x 105 km Sf = 4.25 x 105 km <E>max = 3.7 V/cm
( ) /pd t dt
12 September 2000
Chen and Kunkel (2010)
![Page 10: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/10.jpg)
NRL Solar Physics Division
SENSITIVITY OF FLUX INJECTION TO HEIGHT DATA
D = 1.4% Z0 = 8 x 104 km Sf = 2.0 x 105 km
<E>max ~ 15 V/cm
Initial-value solution from Z0 to 1 AU
Chen and Kunkel (2010)
The main acceleration phase manifests
Alfven timescale B0 and MT0
Must be internally generated by a model
The long-time trajectory is a stringent
constraint on ( ) /pd t dt
![Page 11: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/11.jpg)
NRL Solar Physics Division
CME-FLARE CONNECTION
• Demonstrated for several CME-flare events:
‒ The best-fit solutions constrained by height-time data alone yield —a
physical prediction—in close agreement with ISXR(t) (temporal form)
‒ The height-time data contain no information about X-rays—agreement is significant
• Hypothesis and an interpretation
‒ is a potential drop (super Dreicer) particle acceleration and radiation physical connection between CME and flare particle acceleration
• Physical implications
‒ The time scale of ISXR(t) is in the height-time data—via the ideal MHD EFR equations
‒ The EFR equations capture the correct physical relationship between “M” and “HD”
• Test with another observable quantity
‒ Magnetic field at 1 AU as constrained by the observed CME trajectory data
( ) /pd t dt
(1/ ) ( ) /pemf c d t dt
![Page 12: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/12.jpg)
NRL Solar Physics Division
6.1 New Start Plasma Physics Division
• Best-fit solution is within 1% of the trajectory data throughout the field of view
• If Zdata(t) is used to constrain the EFR equations, the model predicts B1AU(t) correctly
• Arrival time earlier than observed; in this case, a 3D geometrical effect (Kunkel 2012)
BA
Observed B1AU and 3D Geometry
STEREO Configuration 2007 Dec 24
[Kunkel and Chen 2010]
PROPAGATION OF CME and EVOLUTION OF CME B FIELD
Earth
![Page 13: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/13.jpg)
NRL Solar Physics Division
SENSITIVITY OF B(1AU) TO SOLAR QUANTITIES
Dependence of B(1 AU) on injected poloidal energy
• Total poloidal energy injected:
• Vary the flux injection profile while keeping Up|inj unchanged
2 0
( ') ( ')1| '
( ') 'p p
p injt d t
U d tL t d tc
D Bc dΦp/dt (ΔUp)totB(1AU) T(1AU) a(1AU)
[Gauss] [Mx/sec] [erg] [nT] [UT] [km]
0.84 -1.0 4.2 x 1018 9 x 1031 22 61 9.4 x 106
2.97 -1.0 3.6 x 1018 9 x 1031 22 61 9.4 x 106
2.61 -1.0 4.8 x 1018 9 x 1031 22 61 9.4 x 106
• |BCME| and arrival time at 1AU are not sensitive to the flux injection profile
• BCME field and arrival time are most sensitive to injected poloidal magnetic energy
Kunkel (PhD thesis, 2012)
Best fit
![Page 14: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/14.jpg)
NRL Solar Physics Division
MAGNETIC FIELD AND TIME OF ARRIVAL OF CME AT 1AU
• Increase the total injected poloidal energy Up|inj by 10%
‒ Calculate the best-fit solution
‒ Calculate B(1 AU) and time of arrival of CME at 1 AU
‒ Determine the goodness of fit for each solution
D Bc dΦp/dt (ΔUp)tot B1AU T1AU a1AU
[Gauss] [Mx/sec] [erg] [nT] [hrs] [km]
2.87 -1.0 5.6 x 1018 1 x 1032 23 60 9.3 x 106
4.37 -1.0 4.9 x 1018 1 x 1032 24 59 9.1 x 106
2.26 -1.0 5.5 x 1018 1 x 1032 22 61 9.4 x 106
D Bc dΦp/dt (ΔUp)tot B1AU T1AU a1AU
[Gauss] [Mx/sec] [erg] [nT] [hrs] [km]
0.84 -1.0 4.2 x 1018 9 x 1031 22 61 9.4 x 106
2.97 -1.0 3.6 x 1018 9 x 1031 22 61 9.4 x 106
2.61 -1.0 4.8 x 1018 9 x 1031 22 61 9.4 x 106
Best fit
Constant Injected Poloidal Energy
![Page 15: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/15.jpg)
NRL Solar Physics Division
B(1 AU) AND ARRIVAL TIME AT 1 AU: INFLUENCE OF Bc
• The overlying field Bc determines the initial Bp, initial energy, and Alfven time
• Expect the 1 AU arrival time and B(1 AU) to be sensitive to Bc
Sf
R
a
D Bc dΦp/dt (ΔUp)tot B1AU T1AU a1AU
[Gauss] [Mx/sec] [erg] [nT] [hrs] [km]
0.84 -1.0 4.2 x 1018 9.0 x 1031 22 61 9.4 x 106
3.50 -0.5 5.4 x 1018 7.2 x 1031 17.0 60 8.6 x 106
3.36 -1.5 6.8 x 1018 1.5 x 1032 26.1 62 1.0 x 107
0 0 0 0 0 0 0( / ) ln(8 / ),p c pB R a B R a
![Page 16: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/16.jpg)
NRL Solar Physics Division
SUMMARY
The EFR model equations
• A self-contained description of the unified CME-flare-EP dynamics
‒ Correctly replicates observed CME dynamics to 1 AU—a challenge for any CME model
• It can be driven entirely by CME data to compute physical quantities:
‒ — coincides with temporal profile of GOES SXR data (Chen and Kunkel 2010)
‒ B field and plasma parameters at 1 AU — in agreement with data (Kunkel and Chen 2010)
‒ B(1 AU) is not sensitive to the temporal form of ; it is sensitive to the total poloidal energy injected (Kunkel, PhD thesis, 2012; Kunkel et al. 2012)
Physical interpretations of
• is the electromotive force—physical connection to flares
Implications –Space Weather
• Given observed CME trajectory (position-time) data, it is possible to predict the magnetic field at 1 AU—there is sufficient information (Kunkel, PhD, 2012)
• Accurate 1-2 day forecasting is possible if an L5 or L4 monitor exists
( ) /pd t dt
(1/ ) ( ) /pemf c d t dt
( ) /pd t dt
( ) /pd t dt
![Page 17: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/17.jpg)
NRL Solar Physics Division
OPEN ISSUES
Energy Sources
• admits two distinct physical interpretations (Chen 1990; Chen and Krall 2003; Chen and Kunkel 2010)
‒ Coronal source: injection of flux from coronal field via reconnection (conventional)
‒ Subphotospheric source: injection of flux from the solar dynamo (Chen 1989, 1996)
• Neither interpretation has been theoretically or observationally proven
‒ Reconnection: physical dissipation mechanisms and large scale disparity
‒ Subphotospheric mechanism: none has been calculated
• Both are “external physics” in all current CME/flare models
( ) /pd t dt
![Page 18: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/18.jpg)
NRL Solar Physics Division
OTHER MODELS
• The EFR model should be applicable to flux ropes with fixed footpoints
‒ models starting with flux ropes (Chen 1989; Wu et al. 1997; Gibson and Low 1998; Roussev et al. 2003; Manchester et al. 2006)
‒ arcade models producing flux ropes (e.g. Antiochos et al. 1999; Amari et al. 2001; Linker et al. 2001; Lynch et al. 2009)
• Does not apply to axisymmetric flux rope models—e.g., Titov and Demoulin (1999), Lin, Forbes et al. (1998), Kliem and Torok (2006)
‒ They do not correspond to simulations (e.g., Roussev et al. 2003; Torok and Kliem 2008)
• Mathematically, occurs in arcade models (e.g., Lynch et al. 2009)( ) /pd t dt
Titov and Demoulin (1999) Lynch et al. (1999)
![Page 19: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/19.jpg)
NRL Solar Physics Division
PHOTOSPHERIC SIGNATURES?
• Assumptions:
‒ Coherent B field (space and time)
‒ No dynamics
‒
• Schuck (2010)
‒ Smaller A and longer
‒ Same calculation (no dynamics)
AGU Fall (2001)
Lin et al. (2003)
1/V A t
t
![Page 20: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/20.jpg)
NRL Solar Physics Division
• Schuck (2010)
‒ Falsified the “flux injection hypothesis”
‒ Consistent with the “reconnection hypothesis”
• Starting point
‒ Specified coherent field and time scale
‒
‒ No subsurface source of poloidal flux
‒ No dynamical equations of motion for “injection”
‒ No gravity (e.g., no Parker instability)
‒ No convection zone medium through which “injection” occurs
‒ No photosphere (i.e., no photospheric signature)
‒ No reconnection physics or dynamics
• No physical or mathematical basis to support either claim
‒ A “Strawman” argument
• The calculation is the same as Forbes (2001)
OBSERVATIONAL SIGNATURES OF FLUX INJECTION
/ 4 , /c c S E B E V B 0
![Page 21: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/21.jpg)
NRL Solar Physics Division
POLOIDAL FLUX INJECTION
• Poloidal magnetic field is mostly in region—incoherent in dynamics1
Chen (2012, ApJ)(1/ ) 0
0( )
c p
p
J B
J B
![Page 22: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/22.jpg)
NRL Solar Physics Division
Initial Simulation: Chen and Huba (2006)
‒ 3D MHD code (Huba 2003)
‒ A uniform vertical flux rope
‒ Increase B field at the bottom
‒ Introduce a horizontal flow (“convection” flow)
‒ No gravity yet
DYNAMICS OF POLOIDAL FLUX INJECTION
![Page 23: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/23.jpg)
NRL Solar Physics Division
PHOTOSPHERIC SIGNATURES
• Pietarila Graham et al. (2009) –current magnetogram resolution insufficient to resolve small-scale magnetic structures
• Cheung et al. (2010) –Simulation of an emerging flux rope; synthetic magnetograms
‒ Photospheric data show small bipoles; scales are much smaller than the underlying emerging flux rope
Cheung et al. (2010)
![Page 24: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/24.jpg)
NRL Solar Physics Division
END
![Page 25: CME Eruption at the Sun and Ejecta Magnetic Field at 1 AU Valbona Kunkel Solar Physics Division, Naval Research Laboratory Collaborator: J. Chen vkunkel@gmu.edu.](https://reader038.fdocuments.in/reader038/viewer/2022110103/56649cb15503460f949764bf/html5/thumbnails/25.jpg)
NRL Solar Physics Division
POST-ERUPTION ARCADES
Formation of Post-Eruption Arcades
Test the hypothesis that reformation of an arcade results from
Establishes the physical connection between CME acceleration and flare energy release
EUV+H
Jc(t)
(1/ ) ( ) /emf pE c d t dt
Roussev et al. (2003)
( ) /pd t dtJc(t)
Quantities for comparison: temporal profiles
v. 22( ) ( )EUV c pI t J t d dt ( ) /SXR pI t d dt