# Presentation: 722804

## Coronal Mass Ejection (CME) and Space Weather Data Activity

- Ruth Skoug & John Steinberg
- LASSO Teacher Workshop
- July, 2008

## Slide 2

## Slide 3

## Solar wind observations: Dec 1999 - Jan 2000

- Proton density Np typically < 10 particles per cubic centimeter
- Flow speed Vp varies
- ~300-800 km/s
- Increases rapidly, then decreases more slowly
- Proton temperature Tp also varies, ~105 K
- Alpha/proton density ratio Na/Np typically < 5%
- Magnetic field B typically < 10 nT, except at the interface between high speed and low speed solar wind
- North-south component of the magnetic field Bz is quite variable; mean is around 0
- Vp and Tp are correlated

## Speed/Temperature Correlation

- Solar wind speed Vp and temperature Tp are correlated
- This is apparent in the 5-day plots
- We can quantify this by plotting temperature vs speed

## YEAR  	DAY/TIME  	V       	T

- 1999  	364.021  	370   	3.9e+04
- 1999  	364.062 	370  	4.5e+04
- 1999 	364.104	380   	7.0e+04
- 1999  	364.146  	380   	8.9e+04
- 1999  	364.187  	370   	8.5e+04
- 1999  	364.229  	380   	1.1e+05
- 1999  	364.271  	380   	1.2e+05
- 1999  	364.312  	400   	1.3e+05
- 1999  	364.354  	390   	1.1e+05
- 1999  	364.396  	390   	1.1e+05
- 1999  	364.437  	390   	9.3e+04
- 1999  	364.479  	380   	7.4e+04
- 1999  	364.521  	390   	6.5e+04
- 1999 	364.562  	400   	5.3e+04
- 1999  	364.604  	390   	4.9e+04
- 1999  	364.646  	390   	5.4e+04
- 1999  	364.687  	420   	7.8e+04
- 1999  	364.729  	450   	9.9e+04
- 1999  	364.771  	550   	2.3e+05
- 1999  	364.812  	600   	3.2e+05
- 1999  	364.854  	610   	3.0e+05
- 1999  	364.896  	650   	3.7e+05
- 1999  	364.937  	640   	4.1e+05
- 1999  	364.979  	630   	4.2e+05
- NOTE: DAY/TIME given as Day of year + fraction of day
-       Solar wind speed V in km/s
-       Solar wind temperature T in K

## YEAR  	DAY/TIME  	V       	T

- 1999  	365.021  	660   	4.7e+05
- 1999  	365.062  	640   	3.8e+05
- 1999  	365.104  	650   	3.3e+05
- 1999  	365.146  	660   	4.0e+05
- 1999  	365.187  	700  	4.0e+05
- 1999  	365.229  	660   	3.1e+05
- 1999  	365.271  	660   	2.9e+05
- 1999  	365.312  	680   	3.2e+05
- 1999  	365.354  	660   	3.1e+05
- 1999  	365.396  	670   	3.2e+05
- 1999  	365.437  	630   	2.2e+05
- 1999  	365.479  	620   	2.2e+05
- 1999  	365.521  	620   	2.2e+05
- 1999  	365.562  	640   	2.3e+05
- 1999  	365.604  	650   	2.7e+05
- 1999  	365.646  	650   	2.7e+05
- 1999  	365.687  	630   	2.2e+05
- 1999  	365.729  	640   	2.4e+05
- 1999  	365.771  	640   	1.9e+05
- 1999  	365.812  	650   	2.0e+05
- 1999  	365.854 	670   	2.8e+05
- 1999  	365.896  	690   	3.6e+05
- 1999  	365.937  	670   	2.9e+05
- 1999  	365.979  	670   	3.0e+05
- NOTE: DAY/TIME given as Day of year + fraction of day
-       Solar wind speed V in km/s
-       Solar wind temperature T in K

## YEAR  	DAY/TIME  	V       	T

- 2000    	1.021 	670   	2.5e+05
- 2000    	1.062  	700   	2.8e+05
- 2000    	1.104  	710   	3.1e+05
- 2000    	1.146  	720   	3.5e+05
- 2000    	1.187  	710   	3.6e+05
- 2000    	1.229  	720   	3.4e+05
- 2000    	1.271  	750   	3.4e+05
- 2000    	1.312  	760   	3.4e+05
- 2000    	1.354  	750   	2.8e+05
- 2000    	1.396  	770   	2.6e+05
- 2000    	1.437  	730   	2.4e+05
- 2000    	1.479  	730   	2.3e+05
- 2000    	1.521  	740   	2.2e+05
- 2000    	1.563  	730   	2.0e+05
- 2000    	1.604  	720   	2.0e+05
- 2000    	1.646  	720   	1.8e+05
- 2000    	1.688  	710   	1.9e+05
- 2000    	1.729  	710   	1.8e+05
- 2000    	1.771  	740   	2.2e+05
- 2000    	1.813  	720   	2.1e+05
- 2000    	1.854  	710   	1.8e+05
- 2000    	1.896  	720   	1.7e+05
- 2000    	1.938  	700   	1.9e+05
- 2000    	1.979  	700   	1.9e+05
- NOTE: DAY/TIME given as Day of year + fraction of day
-       Solar wind speed V in km/s
-       Solar wind temperature T in K

## YEAR  	DAY/TIME  	V       	T

- 2000    	2.021  	700   	1.9e+05
- 2000    	2.063  	700   	1.9e+05
- 2000    	2.104  	690   	1.8e+05
- 2000    	2.146  	680   	1.7e+05
- 2000    	2.188  	690   	1.7e+05
- 2000    	2.229  	690   	1.9e+05
- 2000    	2.271  	670   	1.9e+05
- 2000    	2.313  	670   	1.9e+05
- 2000    	2.354  	660   	1.9e+05
- 2000    	2.396  	660   	1.8e+05
- 2000    	2.438  	670   	2.1e+05
- 2000    	2.479  	680  	2.4e+05
- 2000    	2.521  	710   	2.4e+05
- 2000    	2.563  	660   	2.0e+05
- 2000    	2.604  	660   	2.1e+05
- 2000    	2.646  	690   	1.9e+05
- 2000   	2.688  	680   	2.1e+05
- 2000    	2.729  	680   	1.6e+05
- 2000   	2.771  	670   	1.4e+05
- 2000    	2.813  	680   	2.0e+05
- 2000    	2.854 	670   	1.9e+05
- 2000    	2.896  	670   	1.8e+05
- 2000    	2.938  	660   	1.3e+05
- 2000    	2.979  	670   	1.1e+05
- NOTE: DAY/TIME given as Day of year + fraction of day
-       Solar wind speed V in km/s
-       Solar wind temperature T in K

## YEAR  	DAY/TIME  	V       	T

- 2000    	3.021  	650   	1.2e+05
- 2000    	3.063  	620   	1.0e+05
- 2000    	3.104  	630   	1.1e+05
- 2000    	3.146  	620   	1.1e+05
- 2000    	3.188  	620   	1.4e+05
- 2000    	3.229  	610   	1.3e+05
- 2000    	3.271  	600   	1.3e+05
- 2000    	3.313  	590  	1.4e+05
- 2000    	3.354  	590   	1.7e+05
- 2000    	3.396  	590   	1.5e+05
- 2000   	3.438  	600   	1.5e+05
- 2000    	3.479  	590   	1.4e+05
- 2000    	3.521  	580   	1.1e+05
- 2000    	3.563  	560   	1.3e+05
- 2000    	3.604  	540   	1.3e+05
- 2000    	3.646  	550   	9.5e+04
- 2000    	3.688  	540   	1.0e+05
- 2000    	3.729  	550   	1.2e+05
- 2000    	3.771  	540   	1.5e+05
- 2000   	3.813  	580   	1.7e+05
- 2000    	3.854  	570   	1.9e+05
- 2000    	3.896  	570   	1.7e+05
- 2000    	3.938  	590   	1.5e+05
- 2000    	3.979  	590   	1.6e+05
- NOTE: DAY/TIME given as Day of year + fraction of day
-       Solar wind speed V in km/s
-       Solar wind temperature T in K

## YEAR  	DAY/TIME  	V       	T

- 2000    	4.021  	590   	1.5e+05
- 2000    	4.062  	590   	1.6e+05
- 2000    	4.104  	590   	1.5e+05
- 2000    	4.146 	590   	1.4e+05
- 2000    	4.187 	600   	1.4e+05
- 2000    	4.229  	600   	1.6e+05
- 2000    	4.271  	590   	1.6e+05
- 2000    	4.312  	600   	1.5e+05
- 2000    	4.354  	630   	2.5e+05
- 2000    	4.396  	630   	2.4e+05
- 2000    	4.437  	600   	1.5e+05
- 2000    	4.479  	600   	1.3e+05
- 2000    	4.521  	590   	1.6e+05
- 2000    	4.562  	580   	1.8e+05
- 2000    	4.604  	560   	1.8e+05
- 2000    	4.646  	570   	1.2e+05
- 2000    	4.687  	570   	1.0e+05
- 2000    	4.729  	530   	1.0e+05
- 2000    	4.771  	550  	9.5e+04
- 2000    	4.812  	560   	8.6e+04
- 2000   	4.854  	540   	9.9e+04
- 2000    	4.896  	510   	1.1e+05
- 2000    	4.937  	520   	9.8e+04
- 2000    	4.979  	520   	1.2e+05
- NOTE: DAY/TIME given as Day of year + fraction of day
-       Solar wind speed V in km/s
-       Solar wind temperature T in K

## YEAR  	DAY/TIME  	V       	T

- 2000    	5.021  	530   	8.3e+04
- 2000    	5.062  	520   	7.2e+04
- 2000    	5.104  	540   	7.8e+04
- 2000    	5.146  	510  	9.8e+04
- 2000    	5.187  	510  	9.5e+04
- 2000    	5.229  	520   	9.3e+04
- 2000    	5.271  	510   	1.3e+05
- 2000    	5.312  	520  	1.4e+05
- 2000    	5.354  	540   	1.1e+05
- 2000    	5.396  	520   	1.1e+05
- 2000    	5.437  	510   	1.3e+05
- 2000    	5.479  	510   	1.5e+05
- 2000    	5.521  	520   	1.4e+05
- 2000    	5.562  	520   	1.6e+05
- 2000    	5.604  	530   	1.5e+05
- 2000    	5.646  	520   	1.6e+05
- 2000    	5.687  	510   	1.6e+05
- 2000    	5.729  	520   	1.6e+05
- 2000    	5.771  	530   	1.4e+05
- 2000    	5.812  	540   	1.1e+05
- 2000    	5.854  	520   	1.7e+05
- 2000    	5.896  	520   	1.5e+05
- 2000    	5.937  	510   	1.5e+05
- 2000    	5.979  	520   	1.3e+05
- NOTE: DAY/TIME given as Day of year + fraction of day
-       Solar wind speed V in km/s
-       Solar wind temperature T in K

## 104

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- 3x105

## Slide 14

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## Slide 16

## Speed/Temperature Correlation

- Solar wind speed Vp and temperature Tp are correlated
- This was apparent in the 5-day plots
- We quantified this by plotting temperature vs speed
- Lab scientists examined this correlation using 3 years of ACE data to determine an “expected temperature” as a function of solar wind speed
- From Dec 30, 1999 to Jan 5, 2000, the expected temperature and the measured temperature are in good agreement

## Slide 18

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## Slide 23

## Speed/Temperature Correlation

- The solar wind speed Vp and temperature Tp are usually correlated, and Tp follows an “expected temperature curve...
- However, at some times, the measured temperature differs from the expected temperature
- At times, Tp is much lower than expected (for a given solar wind speed Vp)
- These times also often show other characteristics
- High alpha/proton density ratio Na/Np
- Southward pointed magnetic field Bz
- Decreasing speed Vp
- Smooth and large magnetic field B

## Solar wind / Magnetosphere Interaction

- The solar wind is a major input to and driver of the Earth’s magnetospheric system
- Coronal mass ejections (CMEs) are a major source of large geomagnetic storms at the Earth

## Effects on the Earth

- Assuming that CMEs can cause geomagnetic storms, predict times when you might expect a geomagnetic storm
- May be a time delay between solar wind observation and response of the magnetosphere
- A geomagnetic storm may be caused by a specific feature in the solar wind, that may or may not exactly correspond to the entire period when a CME was observed

## Geomagnetic Storms

- We will identify geomagnetic storms based on the Dst index
- Dst measures variations in the Earth’s magnetic field
- Units: nanoTesla (nT = 10-9 T)
- Average based on several equatorial magnetometer stations
- Responds to currents in the magnetosphere
- Storm leads to more ions, flowing closer to the Earth, leading to a larger current
- A flowing current makes a magnetic field.  An magnetometer on the Earth measures all magnetic fields, including the intrinsic magnetic field of the Earth **and** all magnetic fields caused by moving ions

## The Dst index measures the variation of the Earth’s magnetic field caused by geomagnetic storms, in units of nT (nano-Tesla).

- A Dst of –50 nT defines a moderate storm; a Dst of –100 defines a major storm.

## The Dst index measures the variation of the Earth’s magnetic field caused by geomagnetic storms, in units of nT (nano-Tesla).

- A Dst of –50 nT defines a moderate storm; a Dst of –100 defines a major storm.

## Slide 30

## Speed/Temperature Correlation

- The solar wind speed Vp and temperature Tp are usually correlated, and Tp follows an “expected temperature” curve
- However, at some times, the measured temperature differs from the expected temperature
- At times, Tp is much lower than expected (for a given solar wind speed Vp)
- These times also often show other characteristics
- High alpha/proton density ratio Na/Np
- Southward pointed magnetic field Bz
- Decreasing speed Vp
- Smooth and large magnetic field B
- _These characteristics identify a Coronal Mass Ejection (CME)_

## CME Identification

- Try to identify coronal mass ejections (CMEs) in solar wind plasma and magnetic field observations
- Hardcopy pictures, 5 days per plot
- Identify times with lower than average solar wind proton temperatures Tp
- Low proton temperature is a common CME signature
- If time allows, can also look for other signatures
- High Na/Np density ratio
- z component of magnetic field Bz south (negative)
- High values of magnetic field B
- Smoothly varying B
- Decreasing speed Vp

## Month:

- Year:

## Month:

- Year:

## Space Weather Forecasting

- Perhaps not surprisingly, results are mixed
- Low plasma temperature (Tp) in the solar wind is often a good indictor that we will see a geomagnetic storm at Earth
- Sometimes combining low Tp with other signatures provides a better indicator
- Sometimes it is not obvious what solar wind inputs caused a geomagnetic storm at the Earth
- Terrestrial weather forecasting provides a good analogy
- Hard to do on Earth, even with many weather stations
- In space, we have only one weather station (or maybe 2-3), which may or may not be located in an optimal location

## Slide 36

## Note preferred order of following plots, if not enough groups to do all:

- A) July - Aug, 1999   (very quiet, min Dst of -50)
- B) Sept - Oct, 2000    (several storms, Dst twice reaches -200)
- C) Aug - Sept, 1998   (several storms)
- D) Apr - May, 2001   (several storms)
- E) Sept - Oct, 2001    (many storms)
- F) Nov - Dec, 1998	    (several storms)
- G) May - Jun, 2000    (several storms)
- H) Mar - Apr, 1999    (very quiet)

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