Coronal Mass Ejections: from the Sun to the Earth Consuelo Cid Space Research Group-Space Weather University of Alcala

Monthly Notices of the Royal Astronomical Society, Vol. 20, November 11, Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Magnetic Observations at Kew Two responses seen in the new photographic recordings of magnetic variations being made at Kew (London) Prompt response (due to X-rays increasing ionospheric ionization) Great Magnetic Storm begins 18 hours later (due to associated emission reaching Earth) 3 Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Solar mass ejections Unmagnetized material (Lindenmann, 1919) A plasma cloud including frozen-in magnetic field loops Plasma including turbulent magnetic fields A “tongue” of magnetic field loops rooted at the Sun A disconnected “plasmoid” or “bubble” Shock wave ahead of a region of enhanced turbulence …. Flux rope (Burlaga, 1988) 4Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

CMES AT THE SUN Coronal Mass Ejections: from the Sun to the Earth 5Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

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The first CME observed in 1860? This early observation was not confirmed convincingly. However... 7Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

The first CMEs observed in modern times: OSO 7 (1971) and Skylab (1973)...the similarity with Skylab images obtained 113 years later is striking! 8Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

This was the first published ‘modern‘ CME event, observed 1971 from OSO 7 9Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

CME?...can’t tell what it is, but if I see it I know it... What, actually, is a CME? Definition of terms: “A coronal mass ejection (CME) is … an observable change in coronal structure that 1) occurs on a time scale of a few minutes and several hours and 2) involves the appearance (and outward motion) of a new, discrete, bright, white-light feature in the coronagraph field of view." (Hundhausen et al., 1984) This definition is very fortunate in that it emphasizes the observational aspect, it stresses the transient event character, it does not infer an interpretation of the "feature" and its potential origin, in particular, it does NOT infer any conjunction with "coronal mass", it restricts the applicability of the term to the Sun's proximity 10Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Just an example of what a CME is 11Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Some CMEs are spectacular, indeed! 12Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Properties of CMEs 13Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

A unique observation by LASCO-C2. Note the helical structure of the prominence and filaments! 14Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

The most popular astronomical picture in history: a huge prominence seen in the He + line (30.4 nm), from Skylab (1973) From that time in 1973 on, CMEs were an issue! 15Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

The helical structure could just disappear because of 2D-projection on the plane of sky 16Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Full halo CMEs: ejections towards or away the Earth 17Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

X-Ray or EUV images show coronal loops anchored in the photosfere 18Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

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Reconnection and CMEs Above CME Release mechanism in “breakout” model Fast CMEs Below CME Release mechanism in “emerging flux” model Slow CMEs 20Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Hight helicity: one of the clues for the “emerging flux” model 21Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

22Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June Checking the “breakout model”: dimming at solar disk

CMEs AT INTERPLANETARY MEDIUM Coronal Mass Ejections: from the Sun to the Earth 23Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Solar wind …and solar wind transients 24Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

ICME signatures in solar wind 25Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

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The first ‘magnetic cloud’ Burlaga et al., 1991 … and the topology proposed 27Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Note the 180º rotation of the magnetic field direction through the cloud! Minimum Variance Analysis 28Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Are all ICME MCs?... …the answer is still on debate Today: Magnetic cloud = flux rope 29Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

From 1D to 3D … well, just 2D+1/2 D 30Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Force-free model (Burlaga, 98)  =cte Lundquist (1950) Boundary: B axial =0  R =2.4 31Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

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MCs expand! Force-free? MCs expand! Force-free? 33Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

First non-force free MC model Plasma and magnetic field inside magnetic clouds: a global study (Cid et al., 2001) The starting point: Analytical expressions: 34Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

X GSE Y GSE Z GSE X GSE Z GSE Y GSE y0y0  º   35Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

The model reproduced properly experimental data… 36Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

.. but not for all MCs. Elliptical MCs Elliptical cross-section model for the magnetic topology of magnetic clouds (Hidalgo, Nieves- Chinchilla and Cid, 2002) It fits well... but many parameters need to be controlled 37Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Reconstruction of the cross section using Grad-Safranov equation But MC boundaries are difficult to be established 38Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Numerical simulations 39Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

From the Sun to L1 Experimental data and models do not agree systematicaly: only a few cases have been reproduced nowadays Where is the problem to be solved? …In the magnetic topology? …In the propagation through the solar wind? … more work needed! 40Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

The problem is still harder! Complex ejecta, multiMC… 41

CMEs AT TERRESTRIAL ENVIRONMENT Coronal Mass Ejections: from the Sun to the Earth 42Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

At solar wind (L1) At the terrestrial surface 43Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

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Energy injected from solar wind (Dungey, 1961): proportional to convective electric field ( E y =VB z ) ICMEs present large values of V and B z 45Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

DPS relation: The decrease of the horizontal component of the geomagnetic field is proportional to the energy content of the ring current From the energy balance in the ring current, it is possible to get the Dst index as a function of time Neglecting losses (main phase): Theoretical scenario Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June

Cumulated E y is not enought to explain the terrestrial disturbance for small  t … but theoretical expectations do not fit properly experimental data Soon appearing in GRL… 47Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June B z standard deviation is large for those events

Both, E convective and  B/  t, are related to the appearance of an induced E EyEy Our results agree with Faraday law!

The phenomena are complicated and without limit as we look to finer and finer detail. It is not our goal to pursue the endless detail; instead, we are interested in understanding what we observe in terms of the basic laws of physics. We want to know how the observed effects follow from Newton, Maxwell, Lorentz, Schorödinger, etc. We construct idealized and simplified theoretical models for the purpose of demonstrating how the basic laws of physics lead to a certain observed effect. We pursue detail only insofar as it leads to novel effects, in which the basic laws of physics interact in some new and hitherto unknown combination.” Eugene N. Parker 49Interdisciplinary Workshop on Plasma Physics, Madrid (Spain), June