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Kinematical properties ofcoronal mass ejectionsManuela TemmerInstitute of Physics, University of Graz, Austria

Evolution of CMEsDisrupted equilibrium (see e.g., Forbes 2000),magnetic reconnection process (fast versusslow reconfiguration, e.g., ‘stealth’ CMEs byRobbrecht et al., 2009)CME front formed due to plasma-pileup /shockcompression of plasma / or successivestretching of magnetic field lines (see reviewe.g., Chen 2011)2-front morphology (see Vourlidas et al., 2013)tworibbonflareSpace Weather effects:(see e.g., Bothmer et al., 2006): Compression ( speed) and magnetic field:energy input E v x Bz Bz (min) related to thermospheric neutraldensity increase (see Krauss et al., 2015)

What do we actually observe?CME speeds, widths, locationsmeasured from single v/p areprojections on the plane-of-sky(e.g., Hundhausen, 1993)All derived parameters are severlyaffected by projection effects (seee.g., Burkepile et al., 2004; Cremadesand Bothmer, 2004)CME WL observations mostly meanto observe the shock-sheath structuredue to shock compression (see e.g.,Ontiveros and Vourlidas, 2009)Temmer and Nitta, 2015Q: Are halo CMEs different from limb CMEs (Chen, 2011)?A: Halo CMEs do not show the actual size of a CME but the fast shock wave(Kwon et al., 2015)

Kinematic properties of CMEsEvolution of CMEs can be divided into three-phasescenario (Zhang et al., 2001; 2004):!Initiation of slow rising motion (some tens of minutes)!Impulsive or major acceleration phase where the maximum ofacceleration and velocity is reached!Propagation phase during which the CMEis adjusted to the speed of the ambientsolar medium (e.g., Chen & Krall, 2003;Vršnak et al., 2004)!First two phases in the inner corona ( 2Rs)(St.Cyr et al., 1999; Vršnak et al., 2001)!Maximum acceleration and velocity mightbe reached very low in the corona ( 0.5Rs)(Zhang & Dere, 2006; Temmer et al., 2008; 2010;Bein et al., 2011)Zhang et al., 2001

Impulsive acceleration phase Detailed h-t profiles enable to study the impulsive acceleration phase withmax. very low in the corona 0.5Rs (Gallagher et al., 2003; Zhang and Dere,2006; Vršnak et al., 2007; Bein et al., 2011) Flare-CME feedback relation (Maričić et al., 2007; Temmer et al., 2008; 2010;Chen and Kunkel, 2010; Bein et al., 2012; Berkebile-Stoiser et al., 2012)Temmer et al. (2010)Maričić et al., 2007

CME dynamics: Lorentz vs. drag forceClose to the Sun propelling Lorentz force asconsequence of magnetic reconnection(e.g. Chen 1989,1996; Kliem & Török 2006)SoHOSTEREOF FL FG FDIn IP space drag acceleration owing tothe ambient solar wind flow (e.g. Vršnak1990; Cargill et al. 1996; Chen, 1996; Cargill2004; Vršnak et al. 2004; 2013; Maloney andGallagher 2010, Carley et al., 2012).

CME properties are set in low coronaCMEs that start at lower heights also reachtheir peak acceleration at lower heights.CMEs that are accelerated at lowerheights reach higher peak accelerations.Bein et al., 2011The acceleration phase duration is proportional to the source region dimensions(compact CMEs are accelerated more impulsively; Vršnak et al., 2007)." a consequence of stronger Lorentz force and shorter Alfvén time scalesinvolved in compact CMEs (with stronger magnetic field and larger Alfvén speedbeing involved at lower coronal heights; Vršnak et al., 2007).

CME mass and energy – low coronaProjection effects - errors of factor 2 at50-60 from from POS (Vourlidas et al., 2000)3D/total mass: use two (or three) differentvantage points (Colaninno and Vourlidas, 2009)3D parameters for mass evolution:m0 1014g – 1016g (r 3Rs; initial mass)Δm(r) mit r 10-20Rs: 2%-6%Kinetic energy: 1023J – 1025J(see Bein et al., 2013)Important for studies on global energetics offlares and CMEs (see e.g., Emslie et al., 2004, 2012)Bein et al., 2013

CMEs in IP space: elongation and geometryFixed-Φ (Sheeley et al., 1999; Kahler & Webb, 2007; Rouillard et al., 2008)Harmonic Mean (Lugaz et al., 2009; Howard and Tappin, 2009)Self Similar Expansion (Davies et al., 2012; Möstl and Davies, 2012)Davies et al., 2012Rollett et al., 2012Remote sensing in-situ:Constrained Harmonic Mean (Rollett et al., 2012; Rollett et al., 2013)Constrained Self Similar Expansion (Rollett et al., 2014)

3D CME propagation direction (2 s/c)Tie-point reconstruction, triangulation(e.g., Liu et al., 2009; Maloney et al., 2009; Mierla et al., 2009;Temmer et al. 2009; Byrne et al., 2010; Liu et al., 2010) Forward fitting of a model to white light images(Thernisien et al., 2006; 2009; Wood et al., 2009) CME mass calculation (Colannino and Vourlidas, 2009;Bein et al., 2013) Polarization ratio techniques(Moran et al., 2009; deKoning et al., 2009)Mierla et al., 2009Wood et al., 2009Thernisien et al., 2006

Environmental conditionsRotation of CMEs and adjustment to ambient magnetic field structure (seee.g., Yurchyshyn et al., 2001; 2009; Vourlidas et al., 2011; Panasenco et al., 2013)Longitudinal/Latitudinal deflection – non-radial motion (e.g., MacQueen et al.,1986; Burkepile et al., 1999; Byrne et al., 2010; Foullon et al., 2011; Bosman et al.,2012; Wang et al., 2014; Möstl et al., 2015)CME propagation and interaction with the ambient SW (e.g., Manchester et al.,2004; Savani et al., 2010, Temmer et al., 2011; Rollett et al., 2014; Mays et al., 2015).STEREO/SECCHI, C.deForest

Solar wind drag effectEmpirical relation by Gopalswamy et al., 2001Observations using LASCO, SMEI, SECCHI data show drag effects (e.g., Tappin2006; Howard et al., 2007; Morrill et al., 2009, Webb et al., 2009; Davis et al., 2010).Drag Based Model (DBM; Vršnak & Žic, 2007; Vršnak et al., 2013)withDisturbed solar wind conditions(Žic, Vršnak, Temmer, 2015):To fully understand the CME propagationbehavior in IP space we need to know thespatial distribution of SW parameters.http://oh.geof.unizg.hr/DBM/dbm.php & swe.uni-graz.at

Preconditioning of interplanetary spaceCME occurrence rate: 0.3 per day (solar min) to 4-5 per day (solar max) e.g.,St. Cyr et al. (2000), Gopalswamy et al., (2006) w/ TT 1-4 days (w/ 500-3000km/s).CMEs may „clear the way“, making follow-up events super-fast (e.g., Liu et al.,2014; Temmer and Nitta, 2015).During times of high solaractivity, preconditioningdue to successive CMEeruptions is highly likely.Odstrćil et al., 2012 (EGU 2012); see also Lee et al., 2015

CME – CME interactionGopalswamy et al. 2001Successive CMEs (similar directions) maymerge and form complex ejecta of singlefronts (e.g., Gopalswamy et al. 2001; Burlaga etal. 2002, 2003; Wang et al. 2002; Wu et al., 2007).Radio enhancements, SEPs – acceleration atshock front or from regions with access tosolar wind magnetic field lines?(e.g., Gopalswamy et al. 2001; 2002; Hillaris et al.,2011; Kahler & Vourlidas 2014)Hillaris et al. 2011Effects at Earth: extended periods of negative Bz(e.g. Wang et al. 2003; Farrugia et al.2006) intense geomagnetic storms (Burlagaet al. 1987; Farrugia et al. 2006a,b; Xieet al. 2006; Dumbović et al., 2015)

Observing the interaction process?Strong deceleration hours before interaction of CME leading edges – transfer ofmomentum (see e.g., Farrugia & Berdichevsky, 2004; Lugaz et al., 2009; Maričić et al.,2014). Interaction process related to MFR location (Temmer et al., 2014).CME2MHDcl eobstaCME1Temmer et al., 2014Temmer et al., 2012 a2 – 2 m/s2 a1 – 40 m/s2

Summary and conclusions CME properties are set in the low corona (source region characteristics,magnetic reconnection process which links flares and CMEs) Ambient magnetic field configuration controls CME kinematics close to Sun(strong overlying fields, see e.g., Thalmann et al., 2015). Propagation behavior of CMEs in IP space strongly affected by thecharacteristics of the ambient solar wind flow CME-CME / CME-HSS interaction: extremechanges in CME dynamics; may happen quite often Preconditioning (density, B) may play an important roleILWS Jan24-29, 2016! CME/Space Weather forecast: tools might need permanent update (implementEACH event!); event-based forecasts might not improve accuracy

Harmonic Mean (Lugaz et al., 2009; Howard and Tappin, 2009) Self Similar Expansion (Davies et al., 2012; Möstl and Davies, 2012) CMEs in IP space: elongation and geometry Rollett et al., 2012 Davies et al., 2012 Remote sensing in-situ: Constrained H