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CME propagation in the interplanetary medium(A review talk)
Jens Kleimann
Theoretische Physik IV,Ruhr-Universität Bochum, Germany
3rd SOLAIRE Network MeetingNovember 05, 2009 � Puerto de la Cruz, Tenerife
A CME’s life: It...gets born, [Initiation models: flux emergence, C. Jacobs]evolves, [Coronal development of CMEs, T. Török]and leaves home to see places. [ ↓ This talk ↓]
1 Motivation2 Observation / Statistics
TrajectoryArrival timesGeo-effectiveness
3 (MHD) Modellinganalyticalnumerical
4 Conclusions
A CME’s life: It...gets born, [Initiation models: flux emergence, C. Jacobs]evolves, [Coronal development of CMEs, T. Török]and leaves home to see places. [ ↓ This talk ↓]
1 Motivation2 Observation / Statistics
TrajectoryArrival timesGeo-effectiveness
3 (MHD) Modellinganalyticalnumerical
4 Conclusions
MotivationObservation / Statistics
(MHD) ModellingConclusions
Why care about CMEs?Major manifestation of solar activity
M ≈ 1012...13 kg, W ≈ 1023...25 Jrate (1...6)/day, ∼10 % of which hit Earth!
CMEs relate to many other fields of Solar physicsflares↔ CMEsparticle acceleration at shocksglobal flux removal...
Commercial application: “space weather”safety concerns for astronautics,satellite communication failures, etc.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
Why care about CMEs?Major manifestation of solar activity
M ≈ 1012...13 kg, W ≈ 1023...25 Jrate (1...6)/day, ∼10 % of which hit Earth!
CMEs relate to many other fields of Solar physicsflares↔ CMEsparticle acceleration at shocksglobal flux removal...
Commercial application: “space weather”safety concerns for astronautics,satellite communication failures, etc.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
Why care about CMEs?Major manifestation of solar activity
M ≈ 1012...13 kg, W ≈ 1023...25 Jrate (1...6)/day, ∼10 % of which hit Earth!
CMEs relate to many other fields of Solar physicsflares↔ CMEsparticle acceleration at shocksglobal flux removal...
Commercial application: “space weather”safety concerns for astronautics,satellite communication failures, etc.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
S/C observations from:LASCO on SOHO (white-lightcoronagraph, 32R� FoV, since 1995)ACE, Wind (in-situ @ L1, since 1997)Helios 1/2 (in-situ @ 0.3 AU, 1974 – ’81)SMEI on Coriolis (white-light, all-sky,since 2003, r > 70R�)STEREO A/B (since 2007)anecdotal: ICME detection via H+
enhancement by Voyager 2 (@ 58 AU)& Ulysses [Paularena et al. 2001]
...
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Main goals: Predict a CME’s...
1. trajectory, 2. arrival time (at Earth), 3. geo-effectiveness
1st order assumption: CMEs expand radially.⇒ Only "halo" CMEs will hit Earth. [Schwenn 2005]:
∼10% of events involved non-halo CMEs (missing alarms)∼10% of halo CMEs miss Earth (false alarms)
Eastward deflection due to Parker spiral?
slow fastCMEs go
East↙ ↘West(noticeably) (slightly)
[Wang et al. 2004]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Main goals: Predict a CME’s...
1. trajectory, 2. arrival time (at Earth), 3. geo-effectiveness
1st order assumption: CMEs expand radially.⇒ Only "halo" CMEs will hit Earth. [Schwenn 2005]:
∼10% of events involved non-halo CMEs (missing alarms)∼10% of halo CMEs miss Earth (false alarms)
Eastward deflection due to Parker spiral?
slow fastCMEs go
East↙ ↘West(noticeably) (slightly)
[Wang et al. 2004]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Main goals: Predict a CME’s...
1. trajectory, 2. arrival time (at Earth), 3. geo-effectiveness
1st order assumption: CMEs expand radially.⇒ Only "halo" CMEs will hit Earth. [Schwenn 2005]:
∼10% of events involved non-halo CMEs (missing alarms)∼10% of halo CMEs miss Earth (false alarms)
Eastward deflection due to Parker spiral?
slow fastCMEs go
East↙ ↘West(noticeably) (slightly)
[Wang et al. 2004]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Main goals: Predict a CME’s...
1. trajectory, 2. arrival time (at Earth), 3. geo-effectiveness
1st order assumption: CMEs expand radially.⇒ Only "halo" CMEs will hit Earth. [Schwenn 2005]:
∼10% of events involved non-halo CMEs (missing alarms)∼10% of halo CMEs miss Earth (false alarms)
Eastward deflection due to Parker spiral?
slow fastCMEs go
East↙ ↘West(noticeably) (slightly)
[Wang et al. 2004]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Main goals: Predict a CME’s...
1. trajectory, 2. arrival time (at Earth), 3. geo-effectiveness
1st order assumption: CMEs expand radially.⇒ Only "halo" CMEs will hit Earth. [Schwenn 2005]:
∼10% of events involved non-halo CMEs (missing alarms)∼10% of halo CMEs miss Earth (false alarms)
Eastward deflection due to Parker spiral?
slow fastCMEs go
East↙ ↘West(noticeably) (slightly)
[Wang et al. 2004]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Main goals: Predict a CME’s...
1. trajectory, 2. arrival time (at Earth), 3. geo-effectiveness
1st order assumption: CMEs expand radially.⇒ Only "halo" CMEs will hit Earth. [Schwenn 2005]:
∼10% of events involved non-halo CMEs (missing alarms)∼10% of halo CMEs miss Earth (false alarms)
Eastward deflection due to Parker spiral?
slow fastCMEs go
East↙ ↘West(noticeably) (slightly)
[Wang et al. 2004]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
CME tracking
STEREO’s dual view can be used to re-construct the 3-D trajectory via stereoscopy.(Well-posed problem for points and curves[Inhester 2006]).
Problems:CMEs are extended, partiallytranslucend objects⇒ tricky toidentify common features in images.S/C launched into "deep" solar min.⇒ only few events to study.
[Maloney et al., submitted]
Preliminary results indicate"quasi-radial" paths.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
CME tracking
STEREO’s dual view can be used to re-construct the 3-D trajectory via stereoscopy.(Well-posed problem for points and curves[Inhester 2006]).
Problems:CMEs are extended, partiallytranslucend objects⇒ tricky toidentify common features in images.S/C launched into "deep" solar min.⇒ only few events to study.
[Maloney et al., submitted]
Preliminary results indicate"quasi-radial" paths.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
CME tracking
STEREO’s dual view can be used to re-construct the 3-D trajectory via stereoscopy.(Well-posed problem for points and curves[Inhester 2006]).
Problems:CMEs are extended, partiallytranslucend objects⇒ tricky toidentify common features in images.S/C launched into "deep" solar min.⇒ only few events to study.
[Maloney et al., submitted]
Preliminary results indicate"quasi-radial" paths.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
CME tracking
STEREO’s dual view can be used to re-construct the 3-D trajectory via stereoscopy.(Well-posed problem for points and curves[Inhester 2006]).
Problems:CMEs are extended, partiallytranslucend objects⇒ tricky toidentify common features in images.S/C launched into "deep" solar min.⇒ only few events to study.
[Maloney et al., submitted]Preliminary results indicate"quasi-radial" paths.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Arrival times (@ 1AU)
Required data:1 initial speed (from coronagraphs, modulo projection)2 pos.(+) / neg.(−) acceleration a en route due to
thermal pressure (+), magnetic forces (±), gravity (−),aerodynamic drag (−), "snow plough-effect" (−)
For r < 32R� : linear height-time-fit ok. [St.Cyr et al. 2000](gradual CMEs: a > 0 out to ∼6 R� [Schwenn et al. 2006])
For r → 1 AU : empirical models for single CMEsProblem: direct CME data only available near Sun(coronagraphs) and Earth (in-situ spacecrafts)
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Arrival times (@ 1AU)
Required data:1 initial speed (from coronagraphs, modulo projection)2 pos.(+) / neg.(−) acceleration a en route due to
thermal pressure (+), magnetic forces (±), gravity (−),aerodynamic drag (−), "snow plough-effect" (−)
For r < 32R� : linear height-time-fit ok. [St.Cyr et al. 2000](gradual CMEs: a > 0 out to ∼6 R� [Schwenn et al. 2006])
For r → 1 AU : empirical models for single CMEsProblem: direct CME data only available near Sun(coronagraphs) and Earth (in-situ spacecrafts)
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Arrival times (@ 1AU)
Required data:1 initial speed (from coronagraphs, modulo projection)2 pos.(+) / neg.(−) acceleration a en route due to
thermal pressure (+), magnetic forces (±), gravity (−),aerodynamic drag (−), "snow plough-effect" (−)
For r < 32R� : linear height-time-fit ok. [St.Cyr et al. 2000](gradual CMEs: a > 0 out to ∼6 R� [Schwenn et al. 2006])
For r → 1 AU : empirical models for single CMEsProblem: direct CME data only available near Sun(coronagraphs) and Earth (in-situ spacecrafts)
⇒ Need to bridge [∼ 0.2,1.0] AU interval.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Solution #1: Trace type II radio emissions from the CME’s upstreamshock, occurring at harmonic f = 9
√n/m−3 MHz
→ n at source region→ positionbut: stand-off distance not known (≤ 0.25 AU at Earth)
Solution #2: Identify CME–ICME pairs, use quadrature observations(1 coronagraph + 1 in-situ S/C over limb) to minimizeprojection effects.
����������
����������
Obs.1
Obs.2
Idea: Relate travel timeT to initial (v0) vs. final(ve) speed.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Solution #1: Trace type II radio emissions from the CME’s upstreamshock, occurring at harmonic f = 9
√n/m−3 MHz
→ n at source region→ positionbut: stand-off distance not known (≤ 0.25 AU at Earth)
Solution #2: Identify CME–ICME pairs, use quadrature observations(1 coronagraph + 1 in-situ S/C over limb) to minimizeprojection effects.
����������
����������
Obs.1
Obs.2
Idea: Relate travel timeT to initial (v0) vs. final(ve) speed.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Arrival time statistics (I)
Bruecker et al. [1998]: Tavg ∼ 80 h(not too bad, esp. at solar min)Lindsay et al. [1999]: linear fit ofve = ve(v0)⇒ v approaches vsw
Gopalswamy et al. [2001]:linear a = a(v0) fit to (v0,T ) datakinematic eq. v0T + aT 2/2 = Rs/c ,→ T = T (v0), ∆T ≈ 10 hbest match if a = 0 beyond 0.75 AU
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Arrival time statistics (I)
Bruecker et al. [1998]: Tavg ∼ 80 h(not too bad, esp. at solar min)Lindsay et al. [1999]: linear fit ofve = ve(v0)⇒ v approaches vsw
Gopalswamy et al. [2001]:linear a = a(v0) fit to (v0,T ) datakinematic eq. v0T + aT 2/2 = Rs/c ,→ T = T (v0), ∆T ≈ 10 hbest match if a = 0 beyond 0.75 AU
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Arrival time statistics (I)
Bruecker et al. [1998]: Tavg ∼ 80 h(not too bad, esp. at solar min)Lindsay et al. [1999]: linear fit ofve = ve(v0)⇒ v approaches vsw
Gopalswamy et al. [2001]:linear a = a(v0) fit to (v0,T ) datakinematic eq. v0T + aT 2/2 = Rs/c ,→ T = T (v0), ∆T ≈ 10 hbest match if a = 0 beyond 0.75 AU
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Arrival time statistics (II)
Schwenn et al. [2005]: Correlationvrad ↔ speed of lateral expansion(defineable w/o projection effects!)⇒ vrad ≈ 0.88 vexp
viscous drag for decel. to vsw = 0
⇒ Th
=
[203− 20.77 ln
(vexp
km/s
)]Cargill [2004]: "aerodynamic" draga(v) ∝ (v − vsw)2 → little difference.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Arrival time statistics (II)
Schwenn et al. [2005]: Correlationvrad ↔ speed of lateral expansion(defineable w/o projection effects!)⇒ vrad ≈ 0.88 vexp
viscous drag for decel. to vsw = 0
⇒ Th
=
[203− 20.77 ln
(vexp
km/s
)]Cargill [2004]: "aerodynamic" draga(v) ∝ (v − vsw)2 → little difference.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Arrival time statistics (II)
Schwenn et al. [2005]: Correlationvrad ↔ speed of lateral expansion(defineable w/o projection effects!)⇒ vrad ≈ 0.88 vexp
viscous drag for decel. to vsw = 0
⇒ Th
=
[203− 20.77 ln
(vexp
km/s
)]Cargill [2004]: "aerodynamic" draga(v) ∝ (v − vsw)2 → little difference.
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
In summary:
1 On average T ≈ 80 h2 v0 highly variable, vcme → vsw for r � R�3 empirical formulas T = T (v0) or T (vexp), but:4 large scatter due to oversimplifaction, CMEs and IP
medium both too variable/structured for simple fitting laws
"[We propose] that a number of CMEs be droppedfrom La Torre di Pisa and their drag force be directlymeasured."
Reiner et al. [2003]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
In summary:
1 On average T ≈ 80 h2 v0 highly variable, vcme → vsw for r � R�3 empirical formulas T = T (v0) or T (vexp), but:4 large scatter due to oversimplifaction, CMEs and IP
medium both too variable/structured for simple fitting laws
"[We propose] that a number of CMEs be droppedfrom La Torre di Pisa and their drag force be directlymeasured."
Reiner et al. [2003]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Geo-effectiveness := ability to cause severe magnetic storms/energetic particle flux at Earth.
Bz < 0 favors interaction with Earth’s magnetosphere:
Bz,cme
{> 0 ⇒ mainly FL repulsion⇒ shielding effect< 0 ⇒ dayside reconnection⇒ particle influx
(plus magnetosphere compression by −∇pcme)Bcme may stem from
1 original flux rope field and/or2 draped/compressed IMF ahead of CME
Fast CMEs have stronger ‖B‖ (but not Bz).[Lindsay et al. 1999]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Geo-effectiveness := ability to cause severe magnetic storms/energetic particle flux at Earth.
Bz < 0 favors interaction with Earth’s magnetosphere:
Bz,cme
{> 0 ⇒ mainly FL repulsion⇒ shielding effect< 0 ⇒ dayside reconnection⇒ particle influx
(plus magnetosphere compression by −∇pcme)Bcme may stem from
1 original flux rope field and/or2 draped/compressed IMF ahead of CME
Fast CMEs have stronger ‖B‖ (but not Bz).[Lindsay et al. 1999]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Geo-effectiveness := ability to cause severe magnetic storms/energetic particle flux at Earth.
Bz < 0 favors interaction with Earth’s magnetosphere:
Bz,cme
{> 0 ⇒ mainly FL repulsion⇒ shielding effect< 0 ⇒ dayside reconnection⇒ particle influx
(plus magnetosphere compression by −∇pcme)Bcme may stem from
1 original flux rope field and/or2 draped/compressed IMF ahead of CME
Fast CMEs have stronger ‖B‖ (but not Bz).[Lindsay et al. 1999]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
TrajectoryArrival timesGeo-effectiveness
Geo-effectiveness := ability to cause severe magnetic storms/energetic particle flux at Earth.
Bz < 0 favors interaction with Earth’s magnetosphere:
Bz,cme
{> 0 ⇒ mainly FL repulsion⇒ shielding effect< 0 ⇒ dayside reconnection⇒ particle influx
(plus magnetosphere compression by −∇pcme)Bcme may stem from
1 original flux rope field and/or2 draped/compressed IMF ahead of CME
Fast CMEs have stronger ‖B‖ (but not Bz).[Lindsay et al. 1999]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
MagnetoHydroDynamics
preferred tool to model underlyingphysics, esp. with respect to non-linearv↔ B interaction.
Analytical works (few in number):
1 The Gibson & Low [1998] flux rope.time-dependent 3-D MHD config;assumes self-similar evolutionstructure of ρ(r) used to create syntheticwhite-light imagesalso used as init for simulations
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
MagnetoHydroDynamics
preferred tool to model underlyingphysics, esp. with respect to non-linearv↔ B interaction.
Analytical works (few in number):
1 The Gibson & Low [1998] flux rope.time-dependent 3-D MHD config;assumes self-similar evolutionstructure of ρ(r) used to create syntheticwhite-light imagesalso used as init for simulations
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
MagnetoHydroDynamics
preferred tool to model underlyingphysics, esp. with respect to non-linearv↔ B interaction.
Analytical works (few in number):
1 The Gibson & Low [1998] flux rope.time-dependent 3-D MHD config;assumes self-similar evolutionstructure of ρ(r) used to create syntheticwhite-light imagesalso used as init for simulations
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
MagnetoHydroDynamics
preferred tool to model underlyingphysics, esp. with respect to non-linearv↔ B interaction.
Analytical works (few in number):
1 The Gibson & Low [1998] flux rope.time-dependent 3-D MHD config;assumes self-similar evolutionstructure of ρ(r) used to create syntheticwhite-light imagesalso used as init for simulations
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
MagnetoHydroDynamics
preferred tool to model underlyingphysics, esp. with respect to non-linearv↔ B interaction.
Analytical works (few in number):
1 The Gibson & Low [1998] flux rope.time-dependent 3-D MHD config;assumes self-similar evolutionstructure of ρ(r) used to create syntheticwhite-light imagesalso used as init for simulations
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Analytical models (cont’d)
2 Flux tube model to probe a CME’sinternal properties [Wang et al. ’09]
requires: self-similarity, J ‖ B, ∂ϕ = 0fixing coefficients c1...6 by[R,L](t) fit to obs. data gives Γcme(t)critical values:Γ ≥ 4/3 : (fem/fth) decreases with rΓ ≥ 2/3 : no more net acceleration
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Analytical models (cont’d)
2 Flux tube model to probe a CME’sinternal properties [Wang et al. ’09]
requires: self-similarity, J ‖ B, ∂ϕ = 0fixing coefficients c1...6 by[R,L](t) fit to obs. data gives Γcme(t)critical values:Γ ≥ 4/3 : (fem/fth) decreases with rΓ ≥ 2/3 : no more net acceleration
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Analytical models (cont’d)
2 Flux tube model to probe a CME’sinternal properties [Wang et al. ’09]
requires: self-similarity, J ‖ B, ∂ϕ = 0fixing coefficients c1...6 by[R,L](t) fit to obs. data gives Γcme(t)critical values:Γ ≥ 4/3 : (fem/fth) decreases with rΓ ≥ 2/3 : no more net acceleration
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Analytical models (cont’d)
2 Flux tube model to probe a CME’sinternal properties [Wang et al. ’09]
requires: self-similarity, J ‖ B, ∂ϕ = 0fixing coefficients c1...6 by[R,L](t) fit to obs. data gives Γcme(t)critical values:Γ ≥ 4/3 : (fem/fth) decreases with rΓ ≥ 2/3 : no more net acceleration
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Space weather prediction relies on large-scale numerical MHD.
CSEM [Toth 2005] CISM [Odstrcil 2008]
Major (technical) challenge: High resolution requirements due to1 need to track features� R� across > 200 R�2 Lack of symmetrysolar min: B� is 2-D, but CME expansion ∦ dipolar axis
solar max: B� is 3-D itself
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Space weather prediction relies on large-scale numerical MHD.
CSEM [Toth 2005] CISM [Odstrcil 2008]
Major (technical) challenge: High resolution requirements due to1 need to track features� R� across > 200 R�2 Lack of symmetrysolar min: B� is 2-D, but CME expansion ∦ dipolar axis
solar max: B� is 3-D itself
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Space weather prediction relies on large-scale numerical MHD.
CSEM [Toth 2005] CISM [Odstrcil 2008]
Major (technical) challenge: High resolution requirements due to1 need to track features� R� across > 200 R�2 Lack of symmetrysolar min: B� is 2-D, but CME expansion ∦ dipolar axis
solar max: B� is 3-D itself
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Solution #1: Ignore ϕ dependence anyway.expansion along polar axis:interesting but somewhat unrealisticexpansion near ecliptic(implies torus-shaped "CME")2-D/3-D comparison [Jacobs et al. 2007]
Solution #2: Performance tuningspecially tailored grids, esp. sphericalwith radially varying ∆r = ∆r(r)
multi-scale models [e.g. Riley et al. ’06]
mesh refinement techniques[BATS-R-US, AMRVAC, ...]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Solution #1: Ignore ϕ dependence anyway.expansion along polar axis:interesting but somewhat unrealisticexpansion near ecliptic(implies torus-shaped "CME")2-D/3-D comparison [Jacobs et al. 2007]
Solution #2: Performance tuningspecially tailored grids, esp. sphericalwith radially varying ∆r = ∆r(r)
multi-scale models [e.g. Riley et al. ’06]
mesh refinement techniques[BATS-R-US, AMRVAC, ...]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Solution #1: Ignore ϕ dependence anyway.expansion along polar axis:interesting but somewhat unrealisticexpansion near ecliptic(implies torus-shaped "CME")2-D/3-D comparison [Jacobs et al. 2007]
Solution #2: Performance tuningspecially tailored grids, esp. sphericalwith radially varying ∆r = ∆r(r)
multi-scale models [e.g. Riley et al. ’06]
mesh refinement techniques[BATS-R-US, AMRVAC, ...]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Solution #1: Ignore ϕ dependence anyway.expansion along polar axis:interesting but somewhat unrealisticexpansion near ecliptic(implies torus-shaped "CME")2-D/3-D comparison [Jacobs et al. 2007]
Solution #2: Performance tuningspecially tailored grids, esp. sphericalwith radially varying ∆r = ∆r(r)
multi-scale models [e.g. Riley et al. ’06]
mesh refinement techniques[BATS-R-US, AMRVAC, ...]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Solution #1: Ignore ϕ dependence anyway.expansion along polar axis:interesting but somewhat unrealisticexpansion near ecliptic(implies torus-shaped "CME")2-D/3-D comparison [Jacobs et al. 2007]
Solution #2: Performance tuningspecially tailored grids, esp. sphericalwith radially varying ∆r = ∆r(r)
multi-scale models [e.g. Riley et al. ’06]
mesh refinement techniques[BATS-R-US, AMRVAC, ...]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Solution #1: Ignore ϕ dependence anyway.expansion along polar axis:interesting but somewhat unrealisticexpansion near ecliptic(implies torus-shaped "CME")2-D/3-D comparison [Jacobs et al. 2007]
Solution #2: Performance tuningspecially tailored grids, esp. sphericalwith radially varying ∆r = ∆r(r)
multi-scale models [e.g. Riley et al. ’06]
mesh refinement techniques[BATS-R-US, AMRVAC, ...]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Solution #1: Ignore ϕ dependence anyway.expansion along polar axis:interesting but somewhat unrealisticexpansion near ecliptic(implies torus-shaped "CME")2-D/3-D comparison [Jacobs et al. 2007]
Solution #2: Performance tuningspecially tailored grids, esp. sphericalwith radially varying ∆r = ∆r(r)
multi-scale models [e.g. Riley et al. ’06]
mesh refinement techniques[BATS-R-US, AMRVAC, ...]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Two types of MHD models
"principal": "realistic":idealized settings, few controlparameters
init near real situation, usesas much physics as possible
Goal: assess importance ofinitial config/ physical effectsfor resulting development
Goal: reproduce (remote/ in-situ) data from actual events
1 Different initialisation methods (→ previous review talks)2 Different realisations of the background solar wind:
uniform [Vandas et al. 1998, 2002]
structured [Odstrcil & Pizzo 1999; Manchester et al. 2004]
realistic [Hayashi et al. 2006; Shen et al. 2007]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Two types of MHD models
"principal": "realistic":idealized settings, few controlparameters
init near real situation, usesas much physics as possible
Goal: assess importance ofinitial config/ physical effectsfor resulting development
Goal: reproduce (remote/ in-situ) data from actual events
1 Different initialisation methods (→ previous review talks)2 Different realisations of the background solar wind:
uniform [Vandas et al. 1998, 2002]
structured [Odstrcil & Pizzo 1999; Manchester et al. 2004]
realistic [Hayashi et al. 2006; Shen et al. 2007]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Two types of MHD models
"principal": "realistic":idealized settings, few controlparameters
init near real situation, usesas much physics as possible
Goal: assess importance ofinitial config/ physical effectsfor resulting development
Goal: reproduce (remote/ in-situ) data from actual events
1 Different initialisation methods (→ previous review talks)2 Different realisations of the background solar wind:
uniform [Vandas et al. 1998, 2002]
structured [Odstrcil & Pizzo 1999; Manchester et al. 2004]
realistic [Hayashi et al. 2006; Shen et al. 2007]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
3 Different physics, e.g. treatment of the energy budget:isothermaladiabatic, γ = γ0 ≤ 5/3
γ = γ(r) [e.g. Fahr et al. ’76, Lugaz et al. ’07]
complete energy equation with
a) ad-hoc heating [e.g. Hartle & Barnes ’70, Manchester ’04]
e.g. Q(r) = q(r) [T0 − γp/ρ] ⇒ T → T0 "target temp."b) consistent Alfvenic wave heating (and pressure) pw:
∂tε± +∇ · [(v± vA)ε±] = −ε±2∇ · v and pw =
ε+ + ε−2
or
∂tP +∇ · [. . .] = ... and pw = 12
∫ fhf0
P(f , r) df
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
3 Different physics, e.g. treatment of the energy budget:isothermaladiabatic, γ = γ0 ≤ 5/3
γ = γ(r) [e.g. Fahr et al. ’76, Lugaz et al. ’07]
complete energy equation with
a) ad-hoc heating [e.g. Hartle & Barnes ’70, Manchester ’04]
e.g. Q(r) = q(r) [T0 − γp/ρ] ⇒ T → T0 "target temp."b) consistent Alfvenic wave heating (and pressure) pw:
∂tε± +∇ · [(v± vA)ε±] = −ε±2∇ · v and pw =
ε+ + ε−2
or
∂tP +∇ · [. . .] = ... and pw = 12
∫ fhf0
P(f , r) df
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
3 Different physics, e.g. treatment of the energy budget:isothermaladiabatic, γ = γ0 ≤ 5/3
γ = γ(r) [e.g. Fahr et al. ’76, Lugaz et al. ’07]
complete energy equation with
a) ad-hoc heating [e.g. Hartle & Barnes ’70, Manchester ’04]
e.g. Q(r) = q(r) [T0 − γp/ρ] ⇒ T → T0 "target temp."b) consistent Alfvenic wave heating (and pressure) pw:
∂tε± +∇ · [(v± vA)ε±] = −ε±2∇ · v and pw =
ε+ + ε−2
or
∂tP +∇ · [. . .] = ... and pw = 12
∫ fhf0
P(f , r) df
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
3 Different physics, e.g. treatment of the energy budget:isothermaladiabatic, γ = γ0 ≤ 5/3
γ = γ(r) [e.g. Fahr et al. ’76, Lugaz et al. ’07]
complete energy equation with
a) ad-hoc heating [e.g. Hartle & Barnes ’70, Manchester ’04]
e.g. Q(r) = q(r) [T0 − γp/ρ] ⇒ T → T0 "target temp."b) consistent Alfvenic wave heating (and pressure) pw:
∂tε± +∇ · [(v± vA)ε±] = −ε±2∇ · v and pw =
ε+ + ε−2
or
∂tP +∇ · [. . .] = ... and pw = 12
∫ fhf0
P(f , r) df
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Findings from principal models (I)
Some indication of nearlyself-similar evolution[e.g. Kleimann et al. ’09]
→ cf. constancy of cone angle[Schwenn et al. 2005]
(relevant for analytical models, etc.)
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Findings from principal models (I)
Some indication of nearlyself-similar evolution[e.g. Kleimann et al. ’09]
→ cf. constancy of cone angle[Schwenn et al. 2005]
(relevant for analytical models, etc.)
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Findings from principal models (I)
Some indication of nearlyself-similar evolution[e.g. Kleimann et al. ’09]
→ cf. constancy of cone angle[Schwenn et al. 2005]
(relevant for analytical models, etc.)
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Findings from principal models (II)
CME evolution depends strongly on1 background SW (e.g. higher speeds in fast, dilute winds,
depends on physics included) [Jacobs et al. 2005] and2 initial topology:{
"Inverse""Normal"
}prom.s give
{fasterslower
}CMEs which deflect
{equatorward.
poleward.
}
[Chané et al. 2006], as predicted by Zhang & Low [2004]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Findings from principal models (II)
CME evolution depends strongly on1 background SW (e.g. higher speeds in fast, dilute winds,
depends on physics included) [Jacobs et al. 2005] and2 initial topology:{
"Inverse""Normal"
}prom.s give
{fasterslower
}CMEs which deflect
{equatorward.
poleward.
}
[Chané et al. 2006], as predicted by Zhang & Low [2004]
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Further challenges:CMEs exhibit diverse structure:Sometimes three parts ("light bulb"[Hundhausen 1988]), but often not.10(!) different morphological classesacc. to Howard et al. [1985]Interaction/merging: About 2 of 3 CMEsare "complex ejecta" [Burlaga 2002]
Incomplete knowledge of IMF structure(accessible only via extrapolation ofnear-surface fields + in-situ data at singlepoints)
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Further challenges:CMEs exhibit diverse structure:Sometimes three parts ("light bulb"[Hundhausen 1988]), but often not.10(!) different morphological classesacc. to Howard et al. [1985]Interaction/merging: About 2 of 3 CMEsare "complex ejecta" [Burlaga 2002]
Incomplete knowledge of IMF structure(accessible only via extrapolation ofnear-surface fields + in-situ data at singlepoints)
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
analyticalnumerical
Further challenges:CMEs exhibit diverse structure:Sometimes three parts ("light bulb"[Hundhausen 1988]), but often not.10(!) different morphological classesacc. to Howard et al. [1985]Interaction/merging: About 2 of 3 CMEsare "complex ejecta" [Burlaga 2002]
Incomplete knowledge of IMF structure(accessible only via extrapolation ofnear-surface fields + in-situ data at singlepoints)
J. Kleimann CME propagation in the interplanetary medium
MotivationObservation / Statistics
(MHD) ModellingConclusions
Conclusions
CMEs show a very diverse phenomenology, thereforepurely kinematic models have limited predictive power.Modelling results crucially depend on physical effectsincluded (e.g. wave heating).As numerical models become more sophisticated, theybenefit from input due to high-quality S/C observations.Nearly self-similar evolution of single(!) CMEs⇒ realistic modelling at small radii is essential!
J. Kleimann CME propagation in the interplanetary medium
(Thank you!)
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