1. The properties of CMEs embedded in extreme solar wind
C. Cid, J. Palacios, A. Guerrero, E. Saiz and Y. Cerrato
Space Weather Research Group
University of Alcalá

2. What does ‘extreme space weather’ mean?
Scale
Physical measure R5
X20 flare (GOES Xray Flux=2x10-3 Watts m-2) S5
Flux level of 10 MeV protons = 105 particles cm-2s-1 sr-1 G5
Kp=9
Scale
Physical measure G5
LDiñ > -300 nT C5
LCiñ > 35 nT min-1
Extreme geomagnetic storms
X-flares

3. What is the trigger of a extreme geomagnetic storm (G5)?
Extreme solar activity (X flares or even fast CMEs) NOT ALWAYS produces extreme geomagnetic storm
But extreme geomagnetic storms ALWAYS happen after extreme solar wind conditions reaching the Earth
What do ‘extreme solar wind conditions’ mean? ?

4. The number of data in the hystogram is not the same for all parameters!

6. In probability theory, statistics and econometrics, the Burr Type XII distribution or simply the Burr distribution[1] is a continuous probability distribution for a non-negative random variable. It is also known as the Singh–Maddala distribution[2]and is one of a number of different distributions sometimes called the "generalized log-logistic distribution". It is most commonly used to model household income 
Household income is a measure of the combined incomes of all people sharing a particular household or place of residence. It includes every form of income, e.g., salaries and wages, retirement income, near cash government transfers like food stamps, and investment gains.
Note when c = 1, the Burr distribution becomes the Pareto Type II (Lomax) distribution. When k = 1, the Burr distribution is a special case of the Champernowne distribution, often referred to as the Fisk distribution.
45 nT

7. All extreme solar wind events (B > 45nT) observed during ACE mission
Year
Month
Day
DoY
2000
July 15
2001
March 31 90
November 6
310 24
328
2002
May 23
143
2003
October 29
302 20
324
2004 7
2005
135
August
236

8. Is B enough to define XXXL solar wind?
All events with Kp=9 or Dst<-300 nT are included in the list, that is, all G5 are included
Good point! Almost no data gap in IMF at L1!
Then, next questions to improve forecasting time:
which are the drivers of B>45 nT?
Is there any common signature in the solar triggers of extreme solar wind?

9. The interplanetary drivers
Year
Month
Day
Trigger
References
2000
Jul 15
Isolated MC?
[1], [2], [5]
2001
Mar 31
Multi-MCs
[1], [2], [3], [4], [5]
Nov 6
Multi-MCs+HSS
[2], [3], [4], [5] 24
Multi-MC
2002
May 23
SH (M)+HSS
[1], [2]
2003
Oct 29
Isolated MC
[1] 20
2004 7
2005
[1], [5]
Aug
[1] Zhang et al. (2007), [2] Xie et al. (2006), [3] Cid et al. (2008), [4] Wang et al. [2003], [5]Cerrato et al. (2011)

10. The interplanetary drivers
Year
Month
Day
Trigger
References
2000
Jul 15
Isolated MC?
[1], [2], [5]
2001
Mar 31
Multi-MCs
[1], [2], [3], [4], [5]
Nov 6
Multi-MCs+HSS
[2], [3], [4], [5] 24
Multi-MC
2002
May 23
SH (M)+HSS
[1], [2]
2003
Oct 29
Isolated MC
[1] 20
2004 7
2005
[1], [5]
Aug
[1] Zhang et al. (2007), [2] Xie et al. (2006), [3] Cid et al. (2008), [4] Wang et al. [2003], [5]Cerrato et al. (2011)

11. In-depth analysis of specific events does not conclude the same
Dasso et al., JGR (2009)

12. Magnetic field vs. compositional anomalies
He2+/H+  0.06 ICMEs (Richardson & Cane, 2004)
<QFe> higher than 10: ICMEs (Lepri & Zurbuchen, 2004)
O7+/O6+ ratio:
Low for streams from CHs (Zurbuchen et al. 2002)
High for ICMEs (Lepri et al ; Henke et al. 2001)
ln(Tp/Np-1)  proton specific entropy
-consequences for the fitting
High O7+/O6+ interval is more than three times that of the MC
Cid et al., ApJ (2016)

13. Let’s double check the three remaining isolated MC triggers based on compositional anomalies

17. Conclusions
Solar wind PDFs since the beginning of the ACE mission have been analyzed
Extreme solar wind has been defined from the outlayers of the B magnitude
All extreme geomagnetic storms were triggered by the solar wind defined as extreme
Drivers of extreme solar wind are the result of the interaction among several solar ejections (probably at the interplanetary medium)

18. Thank you for your attention!