Space weather: solar drivers, impacts and forecasts Henrik Lundstedt Swedish Institute of Space Physics Lund We live inside the continuously expanding solar corona, i.e. the solar wind, which can be very strong e.g. at times of CMEs. Earth is also exposed to very intense radiation at times of so called solar flares. The Sun is also inside a stellar wind and a flow of cosmic rays. This space weather has impacts on both Earths atmosphere and technological systems. To mitigate the effects of the space weather we need to forecast it and start to learn to live with the Sun.

Outline How do we define space weather? How do we observe it? (solar weather) What drives it? (solar activity and solar phenomena) Which are the impacts on: the Earths atmosphere and technological systems? How can we forecast it? What services exist? Todays space weather.

Rymdväder was mentioned the first time in media 1991! The US National Space Weather Program 1995: Space weather refers to conditions on the sun, and in the solar wind, magnetosphere, ionosphere and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and endanger human life or health. LWS 2001 and ILWS ESA Space Weather Programme started in April ESA Space Weather Pilot projects start in April SWWT, EU COST 724 Space Weather. Space weather HD 1981 (cykel 21) SDS 1991 (cycle 22) Arbetet 1981 (cycle 21)

Workshops arranged in Lund Workshops on Artificial Intelligence Applications in Solar-Terrestrial Physics were held in Lund 1993 and John Freeman (Rice University, Houston, TX) coined the word space weather

The Sun Diameter: km (109 x Earth) Mass: 1.99x10 30 kg ( x Earth) Density: Core 151x10 3 kg/m -3 Average 1.41 x10 3 kg/m -3 The Sun consits of: H ( 90%) Helium ( 10%) C,N,O ( 0.1%) Temperature: Core 15 million Photosphere 5800 K Chromosphere K Corona 1-30 million K 4 protons --> He + 2 positrons + 2 neutrinos + 2 fotons (26.2 MeV)

A plasma A plasma is a quasineutral gas of charged and neutral particles, which exhibits collevtive behavior. Three conditions a plasma must satisfy.

Xspace from UCLA

Plasma equations Macroscopic plasma quantities: By taking velocity moments of the particle distribution function f s (x,v,t) for particles of species s in six-dimensional phase space we obtain macroscopic measurable quantities such as bulk velocity, pressure and the temperature. Macroscopic equations: By taking velocity moments of the Vlasov equation we obtain the fluid equations of a plasma in terms of the macroscopic variables. The zeroth and first order moments, result in continuity equation and fluid equation of motion.

Magnetohydrodynamic (MHD) approximation Induction equation Equation of continuity Equation of motion Maxwell equations and Ohms law give the induction equation. We need to observe V and B.

Solar observations Where on Earth do we observe the Sun? What spacecrafts observe the Sun? How do we observe V and B on the Sun?

Solar observations in California Mount Wilson Observatory Big Bear Solar Observatory Wilcox Solar Observatory Internet-accessible robotic solar telescope in Livermore

French solar observation facilities Pic du Midi (Coronagraph, (Lyot) THEMIS on Tenerife (solar magnetic field) Radioheliograph at Nancay (CMEs)

Solar observations with the Swedish solar telescope on La Palma

Advanced Technology Solar Telescope 4-m telescope 0.1 resolution Operational 2009 National Solar Observatory

antennas with receivers and senders, arranged in 100 clusters distributed withi a circle of 350 kms diameter. Data transfer rate 25 Tbits/s. Frequency MHz (30-1.5m) Probing CMEs in radio wavelengths with a solar radar in Sweden

ACE was launched in August 25, 1997 Solar wind observations with ACE make accurate forecasts 1-3 hours ahead possible.

STEREO - planned launch November 2005

Solar Orbiter - planned launch 2009 Study the Sun from close-up (45 solar radii,.21 au), (0.05 arcsec) latitude as high as 38 degrees

SDO - planned launch April 2008 Geosynchronous orbit

Living with a Star (LWS)

SOHO was launched on 2 December 1995

SOHO 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?

Dopplergram shows the solar rotation

Dopplergrams show the solar oscillations

How do we observe the solar magnetic field?

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

The Sun Diameter: km (109 x Earth) Mass: 1.99x10 30 kg ( x Earth) Density: Core 151x10 3 kg/m -3 Average 1.41 x10 3 kg/m -3 The Sun consits of: H ( 90%) Helium ( 10%) C,N,O ( 0.1%) Temperature: Core 15 million Photosphere 5800 K Chromosphere K Corona 1-30 million K 4 protons --> He + 2 positrons + 2 neutrinos + 2 fotons (26.2 MeV)

The oscillations reveal solar interior The oscillations at the surface of the Sun are reflections of the standing sound waves that fill the interior. Each standing wave (or n, l, m mode) is trapped between the surface and some critical depth.

A standard solar model L = luminosity (amount of energy radiated per unit time, measured in watts) = energy generated per unit mass per unit time in the core = opacity Energy transferred by radiation by convection The mass equation, equation of hydrostatic equilibrium, equation for energy balance and equation for radiation energy transfer determine the evolution of the Sun. The model must reproduce the observed luminosity and radius of the Sun at its present age from the solar mass, initial chemical composition and age.

Sound speed reveals temperature of solar interior

Sound speed reveals rotation conditions in solar interior

Solar waves reveal the source of solar magnetic activity

Why a flux tube emerges thru the solar surface

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

Why sunspots live so long MDI shows how magnetic elements form sunspots (local helioseismology)

Sunspots on far side

Butterfly diagram

Sunspot solar cycles Schwabe found the 11- year sunspot solar cycle. R = k(10g + f). Gleissberg found the years cycle. Maunder-Spörer 207 years cycle, Houtermans cycle 2272 years and Sharma years cycle. The two peaks of solar activity, 1.3 years separated!

A Maunder minimum suddenly? In the beginning of 1640 the sunspot number suddenly decreased to near zero. The Maunder Minimum started 1645 and ended 1715.

The number of severe proton events follow the Gleissberg cycle and might increase with a factor A maximum occurred A new warm Grand Maximum ( ) has been suggested by J. Lean Gleissberg maximum? (The Carington event 1859 September 1 produced a white light flare, >30MeV proton fluency 4-8 times worst case 1972, a CME v=2500km/s, 18h later a super- storm with Dst = -1760nT!).

Rapid changes for other solar type stars HD (K0V years) multiple cycles HD 9562 (G2V) Maunder minimum state HD (G8V) chaotic HD (F8IV) 23 yearsSun (G2V) 10.0 yearsHD (K1V) 9.6 years For a solar type star the luminosity decreased with 0.4%på in just a few years. Similar rapid changes happened during the Maunder minimum! (compare !) Mount Wilson studies

Non-linear chaotic solar dynamo (N. Weiss) A complex generalization of the three ordinary Lorenz diff equations. The toroidal magnetic field for a dynamo. As the dynamo number D increases D1 (no activity) -> D2 (cycle activity) -> D3 (chaotic activity)

meridional Dynamo Peter Gillman and Mausumi Dikpati (Astrophys. J, 2001)

Our scientific approach

Web page

Solar activity and temperature during longer periods J. Eddy 1976 Meton (in Greece) claimed 400 B.C. that high solar activity was related to wet climate.

Christmas day during Maunder minimum Its heavily snowing in Rome and on the French riviera. Children are skating on Thames River in London and they have annual frost fairs. In Amsterdam the canals are frozen. In Paris the snow is deep. Europa experienced Little Ice Age.

Lund during the Middle Ages and the Maunder minimum The Danish kingdom during Knud the great (1016). During the Middle Ages Lund prospered, Lund was called the capital of Denmark (Metropolis Daniea). Rich could drink excellent wine from England (e.g. from Abbey of Abingdon). Today Bothy Vineyard, south of Oxford. The Swedish king Karl X Gustaf looks at the ice before the crossing of the Belts The battle in Lund follows in December 4, 1676 and Lund becomes Swedish.

Wavelet studies of solar activity and global temperature - trends The Sun has never been as active as after 1940 during the last 1000 years (Phys. Rev. Lett. 2003)

Solar Activity and Earths Climate

The evolution of the grand atmosphere: the solar atmosphere The solar luminosity (total energy output per unit time in the form of electromagnetic radiation). The total flux at mean distance of the Earth from the Sun, the total irradiance at mean distance or solar constant S. S = L/4 A 2. S=1367± 3W/m 2, L=(3.844± 0.010)x10 26 W The solar luminosity has increased during its main-sequence life from 0.7L to the present value. A reduction today of S by a factor 0.7 would probably have lead to a complete ice cover of Earth. Geological evidence suggests it never was. The solution of the puzzle probably lies in the evolution of the Earths atmosphere. The Suns radius has increased from about 0.87r to present radius. Three billions years from now, the Suns radius has increased so much that the oceans on earth has vaporized. About 7.5 billion years from now the Sun is transferred into giant star engulf Earth, melts away everything and then ends as a white dwarf not bigger than earth.

Solar radiation variation with the solar cycle

Real-time Helioseismological Data SDO 2007 Historical Data SOHO/MDI

Solar activity --> UV-radiation --> Ozone --> North Atlantic Oscillation --> T Drew Shindells (NASA GSFC) models show that weak UV (i.e. low solar activity), results in lower amount of ozone, which influences AO/NAO and herwith cause a decrease of the temperature (MM locally1.5C). Maunder Minimum

Solar winds effect on climate ( GRL, Vol 29, No.15, 2002 )

A possible explanation of the solar influence on climate Many sunspots high solar activity Less cosmic radiation Less clouds formed Increase temperature warmer climate The solar corona magnetic field has increased with131% since Cloudes have 100 times more effect on weather and climate than CO 2. The effects of a doubling of the CO 2, that is stated to happen within 100 years could a cloud coverage change Counteract in 3.5 years! The Maunder minimum could be explained.

Will the change of Earths magnetic field influence climate?

The solar influence on Earths weather and climate

END Part 1