Mike Lockwood STFC/Rutherford Appleton Laboratory & Southampton University Our life-giving star: the flow of energy from the Sun to the Earth BA Festival of Science, York, Monday 10 th September 2007 How the Sun Influences Modern Life

Galactic Cosmic Rays Solar Energetic Particles Satellite Damage Human Spaceflight Hazards Sun and Climate Change

How the Sun Influences Modern Life Galactic Cosmic Rays Solar Energetic Particles Satellite Damage Human Spaceflight Hazards Sun and Climate Change

The Solar Wind Plasma A Coronograph is a man-made eclipse with an occulting disc blocking out the visible surface of the Sun (the Photosphere). Allows us to observe the hot solar atmosphere, the Corona Continuous outflow of ionised gas (“plasma”), The Solar Wind,  kg per day Events CMEs eject ~10 13 kg at about 350 km s -1 (PS watch the comet!)

The “Frozen-in flux” Theorem Charged particle motions Magnetic Field B ( by definition of B ) Lorentz Force B B

Emergence of Coronal Magnetic Flux Loops of magnetic flux emerge through the surface in active (sunspot) regions Some of this flux is “open” rises through the corona and is frozen-in to the solar wind outflow

Parker Spiral (an example of frozen-in) Sun Solar wind flow is radial  Solar rotation and radial solar wind generates a Parker spiral field structure  Field is “frozen-in” to the solar wind flow

Sun Solar wind flow is radial  Solar rotation and radial solar wind generates a Parker spiral field structure  Field is “frozen-in” to the solar wind flow Parker Spiral (an example of frozen-in)

Sun Solar wind flow is radial  Solar rotation and radial solar wind generates a Parker spiral field structure  Field is “frozen-in” to the solar wind flow Parker Spiral (an example of frozen-in)

Sun Solar wind flow is radial  Solar rotation and radial solar wind generates a Parker spiral field structure  Field is “frozen-in” to the solar wind flow Parker Spiral (an example of frozen-in)

Sun Solar wind flow is radial  Solar rotation and radial solar wind generates a Parker spiral field structure  Field is “frozen-in” to the solar wind flow Parker Spiral (an example of frozen-in)

Sun Solar wind flow is radial  Solar rotation and radial solar wind generates a Parker spiral field structure  Field is “frozen-in” to the solar wind flow Parker Spiral (an example of frozen-in)

Sun Solar wind flow is radial  Solar rotation and radial solar wind generates a Parker spiral field structure  Field is “frozen-in” to the solar wind flow Parker Spiral (an example of frozen-in)

Sun Solar wind flow is radial  Solar rotation and radial solar wind generates a Parker spiral field structure  Field is “frozen-in” to the solar wind flow Parker Spiral (an example of frozen-in)

Sun Solar wind flow is radial  Solar rotation and radial solar wind generates a Parker spiral field structure  Field is “frozen-in” to the solar wind flow Parker Spiral (an example of frozen-in)

Sun Solar wind flow is radial  Solar rotation and radial solar wind generates a Parker spiral field structure  Field is “frozen-in” to the solar wind flow Parker Spiral (an example of frozen-in)

Sun Solar wind flow is radial  Solar rotation and radial solar wind generates a Parker spiral field structure  Field is “frozen-in” to the solar wind flow Parker Spiral (an example of frozen-in)

 Interplanetary scintillation is the “twinkling” if radio stars caused by irregularities in the solar wind  Tomographic reconstruction from interplanetary scintillations  Solar rotation and radial solar wind generates a Parker spiral field structure  Co-rotates with the solar corona (every 27 days in Earth’s frame) Parker Spiral (an example of frozen-in)

A Stellar Heliosphere interstellar wind bow shock heliopause heliosheath  Hubble observations of the heliosheath behind the bow shock where the heliosphere of LL Ori heliosphere meets its (dense) local interstellar wind in the Orion nebula

Galactic Cosmic Rays The coronal source flux is dragged out by the solar wind flow to give the heliospheric field which shields Earth from galactic cosmic rays

Cosmic Rays Anticorrelation with sunspot numbers Sunspot Number Huancauyo – Hawaii neutron monitor counts (>13GV) Climax neutron monitor counts (>3GV)

A Stellar Heliosphere Cosmic ray tracks in a bubble chamber

How the Sun Influences Modern Life Galactic Cosmic Rays Solar Energetic Particles Satellite Damage Human Spaceflight Hazards Sun and Climate Change

Solar Energetic Protons (SEPs)  Energised at the shock fronts of CMEs (and CIRs)  Follow heliospheric field lines  Seen here striking the imager CCD plate of the LASCO coronograph on the SoHO spacecraft

Sun Parker Spiral (an example of frozen-in)

Sun  SEPs generated at front of CMEs  Guided along IMF Parker Spiral (an example of frozen-in) CME

How the Sun Influences Modern Life Galactic Cosmic Rays Solar Energetic Particles Satellite Damage Human Spaceflight Hazards Sun and Climate Change

Spacecraft Damage spacecraft penetrating radiation electronics box sensitive component charge buried in insulator can discharge floating circuit trace can collect charge and discharge radiation environment damage:  Surface charging  0.1 – 100 keV electrons  Single event upsets  MeV ions  Cumulative radiation dose  Limits spacecraft lifetime  Internal charging (“deep dielectric charging”)  MeV electrons

 Tomographic reconstruction from interplanetary scintillations The Bastille Day Storm CMEs seen by IPS

► Ground-level enhancement (GLE) of solar energetic particles seen between Forbush decreases of galactic cosmic rays caused by shielding by the two CMEs ► Here seen at stations in both poles (McMurdo and Thule) Neutron Monitor counts Forbush decrease caused by 1 st CME GLE Forbush decrease caused by CME associated with GLE nm counts The Bastille Day Storm GCRs and SEPs

 ▲▼ = Single event upsets (SEUs) suffered by satellites in geostationary and high altitude orbits  several satellites were powered down to protect them The Bastille Day Storm SEPs seen at Geostationary Orbit

How the Sun Influences Modern Life Galactic Cosmic Rays Solar Energetic Particles Satellite Damage Human Spaceflight Hazards Sun and Climate Change

BIOLOGICAL EFFECTS Heavy ions breaks molecular links & can cause nuclear reactions so (e.g.) C converted to N and O in molecules

The Apollo Missions

Above annual dose SEPs: just how lucky were the lunar astronauts?  SEPs during the era of the Apollo Missions Raised cancer risk Severe radiation sickness Severe radiation sickness Instantly fatal Average annual dose at Earth’s surface Max. annual dose for a radiation worker

SEPs: what’s the space weather been like? Above annual dose Raised cancer risk Severe radiation sickness Instantly fatal  SEPs and Galactic cosmic rays since the Apollo Missions

How the Sun Influences Modern Life Galactic Cosmic Rays Solar Energetic Particles Satellite Damage Human Spaceflight Hazards Sun and Climate Change

Total Solar Irradiance  best composite of observations (by PMOD, Davos)  shows 0.1% solar cycle variation  damped out by large thermal capacity of Earth’s oceans  but are there century- scale changes which would not be damped?

Total solar irradiance changes and magnetic field emergence  Dark sunspots and bright faculae are where magnetic field threads the solar surface

TSI reconstructions  Open Solar Flux, F S  TSI (for 3 assumptions for the Maunder Minimum) A. [F p ] MM = [F p ] now B. [F p ] MM = 0 C. [F p ] MM = [F p ] now /2

Recent trends - revealed by averaging over solar cycle length, L ► sunspot number, R ► F S from IMF data ► GCR counts C (Climax n.m.) ► PMOD composite of TSI data ► solar cycle length, L running mean over T=[9:(1/4):13] yrs running mean over T=L yrs