living with our star henrik lundstedt swedish institute of space physics the sun drives a space...

Living with our starHenrik Lundstedt

Swedish Institute of Space Physicswww.lund.irf.se

The Sun drives a space weather, that influences the atmosphere, technological systems and us. Our society has become more susceptible tothese effects. We therefore need to start learninghow to live with our star! I will tell how!

OutlineOutline

• How and why does the Sun vary?• How does the Earth respond?• What are the impacts on life and society?• How can we forecast it?• What services exist?• Teach space weather.• Today’s space weather.

The SunThe Sun

Diameter:1 390 000 km(109 x Earth)

Mass:1.99x1030 kg(330 000 x Earth)

Density:Core 151x103 kg/m-3

Average 1.41x103 kg/m-3

The Sun consits of:H (≈ 90%)Helium (≈ 10%)C,N,O ( ≈ 0.1%)

Temperature:Core 15 millionPhotosphere 5800 K Chromosphere 4300-104KCorona 1-30 million K 4 protons --> He + 2 positrons + 2 neutrinos + 2 fotons (26.2 MeV)

Xspace from UCLAXspace from UCLA

Magnetohydrodynamic (MHD) approximation

Magnetohydrodynamic (MHD) approximation

Induction equation

Equation of continuity

Equation of motion

Maxwell’ equations and Ohm’s law give the induction equation.

We need to observe V and B.

Solar observationsSolar observations

• Where do we observe the Sun?

• How do we observe the solar rotation and oscillations?

• How do we observe the solar magnetic field?

Solar observations in California Solar observations in California

Mount Wilson Observatory

Big Bear Solar Observatory Wilcox Solar

Observatory

Internet-accessible robotic solar telescope in Livermore

Solar observations with the Swedish solar telescope on La Palma

Solar observations with the Swedish solar telescope on La Palma

SOHO has given us a totally new picture of the Sun- always activeSOHO has given us a totally new picture of the Sun- always active

• Solar Heliospheric Observatory was launched on December 2, 1995

• SOHO carries three instruments observing the solar interior, six the solar corona and three the solar wind

How do we observe the solar rotation and oscillation?

How do we observe the solar rotation and oscillation?

I =12I 0(λ+ΔλB)+I0(λ −ΔλB)[ ],V =

12I0(λ+ΔλB)−I0(λ −ΔλB)[ ]

vB =ΔλB /ΔλD,ΔλB =4.7⋅10−8gλ2B,ΔλD =(2RT/A)λ /c,v=Δλ / ΔλD

ΔλB <<ΔλD ⇒ V =vBdIdv

,λ =525.05nm,ΔλD =42mÅ,g =3,r0 =0.7⇒

V / I ≈9.6×10−4B,B=10gauss⇒ 1%−cirkulär−polarisation

Dopplergram shows the solarrotation

Dopplergram shows the solarrotation

Dopplergrams show the solaroscillations

Dopplergrams show the solaroscillations

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The oscillations reveal solar interior

The oscillations reveal solar interior

How do we observe the solar magnetic field?

How do we observe the solar magnetic field?

I =12I 0(λ+ΔλB)+I0(λ −ΔλB)[ ],V =

12I0(λ+ΔλB)−I0(λ −ΔλB)[ ]

vB =ΔλB /ΔλD,ΔλB =4.7⋅10−8gλ2B,ΔλD =(2RT/A)λ /c,v=Δλ / ΔλD

ΔλB <<ΔλD ⇒ V =vBdIdv

,λ =525.05nm,ΔλD =42mÅ,g =3,r0 =0.7⇒

V / I ≈9.6×10−4B,B=10gauss⇒ 1%−cirkulär−polarisation

When the solar magnetic field emerges thru the solar suface sunspots appearWhen the solar magnetic field emerges thru the solar suface sunspots appear

MDI/SOHO reveals the interiorMDI/SOHO reveals the interior

MDI shows how magnetic elements form sunspots

MDI shows how the dynamo changes

Sunspots are footpointsof emerging magnetic flux tubes

Sunspots observed on solar surface

Sunspots observed on solar surface

Schwabe found the 11- year sunspot solar cycle. R = k(10g + f)

The two peaks of solar activity, 1.3 years separated!

At solar maximum 100 times brighter X-ray emission and 0.1 % brighter in

visible

At solar maximum 100 times brighter X-ray emission and 0.1 % brighter in

visible

Coronal mass ejectionsCoronal mass ejections

CMEs cause the most severe space weather effects

CMEs cause the most severe space weather effects

• Halo CMEs are most geoeffective

• Mass: 5-50 billion tons

• Frequency: 3.5/day (max), 0.2/day (min)

• Speed: 200-2000 km/s

Solar flares and sun quakesSolar flares and sun quakes

The source of the fast solar wind The source of the fast solar wind

Earth’s responseEarth’s response

• Geomagnetic disturbances

• Aurora

• Ionospheric disturbances

• Climate and weather changes

Earth’s magnetosphere and current systems

Aurora ovalAurora oval

The aurora observed inStockholm

Aurora was observed in Italy 6-7 April and on July 15-16, 2000!

Aurora during severe solar storms

Aurora during severe solar storms

Solar activity and North Atlantic Oscillation Index

Solar activity and North Atlantic Oscillation Index

The NAO response on increased solar wind E, one month later! That makes forecasts one month ahead possible.

North Atlantic Oscillation and solar wind activity

North Atlantic Oscillation and solar wind activity

11 års, 1.3 variations are seen both insolar wind and NAO.

Impacts on life and societyImpacts on life and society

• Human radiation exposure (space station, space exploration (Mars), high altitude flights)

• Impacts on technology (space systems (satellites), communications, navigation, terrestrial systems (electric power grids))

• Terrestrial climate

Satellite anomalies of July 14-16, 2000 eventSatellite anomalies of July 14-16, 2000 event

The proton event causedproblems for ACE,SOHO, Ørsted, Japanese X-ray satellite,star trackers on boardcommercial satellites.

Proton flux (pfu) > 10 MeV,24000 pfu (July 15, 12.30 UT). Third largest!

Largest 43 000 pfu, (March 24, 1991). Second 40 000 pfu (October 20, 1989).

Today IRF-Lund has real-time neural networks forecasts of satellite anomalies one day in advance (ESA project SAAPS). The work has been in collaboration with Swedish satellite operators (ESRANGE).

Solar proton events are dangerous to man in space

Solar proton events are dangerous to man in space

Between Apollo 16 and 17 a proton event occurred, which should have been deadly to the astronautes within10 hours (i.e. above 4000 mSv).

Mars

Radiation risks and aviationRadiation risks and aviation

The radiation exposure is doubled every 2.2 km.

Solar flares can increase the radiation by 20-30 times.

Pilots get cancer more often than average.

New EU law:Pregnant (aircrew) should not be exposed to morethan 1 (1-6) millisievert/year

The intensive solar flare of April 2, 2001, which causedmajor communication problemsalso made ContinentalAirlines to changetheir route betweenHong Kong and New York.

IRF-Lund collaborates with the Swedish Radiation Protection Institute and Medical University in Stockholm to develop forecasts of radiation doses for Aviation Industry.

Power systems and pipeline systemsare effected at times of geomagnetic storms

Power systems and pipeline systemsare effected at times of geomagnetic storms

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This severe electrojet caused the failure of Quebec’s power system March 13-14, 1989. One of the generators of OKG’s

(Sydkraft’s) nuclear plants was heated due to the geomagnetically induced current in March 13-14 1989.

We in Lund have collaborated with the Swedish power industry during more than twenty years. Today we have real-time neural network forecasts of local GICs, based on ACE solar wind and warnings based on SOHO (LASCO and MDI) data.

Measured (SydGas)geomagnetically induced disturbance at time of theNordic GIC meeting in Lund September 23-24, 1999.

ForecastsForecasts

• Forecasting is a central problem within science• Forecasts based on knowledge-based neural model

(KBNM) have been most succesful• Why not teach students how to forecast and model with

KBNM?

Workshops arranged by usWorkshops arranged by us

Workshops on ”Artificial Intelligence Applications in Solar-Terrestrial Physics” were held in Lund 1993 and 1997.

Artificial neural networksArtificial neural networks

The basic element of every ANN is an artificial neuron or simply a neuron (which is an abstract model of a biological neuron (nerve cell)).

Download Lund Dst model in Java

Download Lund Dst model in Java

The ARMA filter is obtained by adding auto-regressive terms to a MA filter.The partial recurrent network (Elman) becomes identical to a linear ARMA filter if it is assigned linear

activations functions.

Test Dst forecastsTest Dst forecasts

Space weather serviceSpace weather service

• Real-time solar data

• International Space Environment Service (ISES)

• 11 Regional Warning Centers (RWC)

• RWC-Sweden in Lund

• H. Lundstedt Deputy Director

Real-time forecasts and warnings based on KBN Real-time forecasts and warnings based on KBN

Solar wind observations with ACE make accurate forecasts 1-3 hours ahead possible.

Solar observations with SOHO make warnings 1-3days ahead possible.

Solar input data

ESA/Lund Space Weather Forecast Service

ESA/Lund Space Weather Forecast Service

Near and farside solar activity from MDI/SOHO observationsNear and farside solar activity from MDI/SOHO observations

Latest information on arrival of halo CME at L1

Latest information on arrival of halo CME at L1

Latest info on forecasts of satellite anomalies (SAAPS)Latest info on forecasts of

satellite anomalies (SAAPS)

Latest information on forecasts of Kp, Dst, AE and GIC

Latest information on forecasts of Kp, Dst, AE and GIC

Regional Warning CentersRWC-Sweden in Lund

Regional Warning CentersRWC-Sweden in Lund

Forecasts of aurora as SMS, voice messages or WAP service

Forecasts of aurora as SMS, voice messages or WAP service

Teach space weatherTeach space weather

• Web sites (SOHO Explore links, Lund Space Weather Center)

• Software packages (Xspace, Lund Dst-model in Java or Matlab

• Books

• CD-ROM ”SOHO - Explore the Sun”

Where to learn more?Where to learn more?

Today’s Space WeatherToday’s Space Weather

Stanford collaborationStanford collaboration

Space weather effects on technological systems

Space weather effects on technological systems

The basic element of every ANN is an artificial neuron or simply a neuron (which is an abstract model of a biological neuron (nerve cell)).

The neuron receives signals (information) from other nerve cells thru the dendrites. The axons take information away from the neuron. The output of the neuron is y=f(wixi), with x as input vector.The value y is the state of the neuron. If f=sgn then the state of the neuron is (+1,-1).

x1x2xnyw1w2wnf(wixi)l

l

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Artificial Neural networksArtificial Neural networks

Proton events give positiveNAO within days!

A User: Power sytem operators

User of NAO forecastsUser of NAO forecasts