Sun is PLASMA – an electrically- magnetically charged gas. 70% Hydrogen, 20% helium and 2% heavier elements Sun is a madhouse of electromagnetic activity On the Sun, almost everything is electrically conductive because there aren’t very many intact neutral atoms Overwhelming thermal and radiation energies excite electrons to the point at which they pop off their atoms, creating a seething stew of positively charged nuclei and free negative electrons – this gaseous mix that conducts electricity as good as copper wire is called PLASMA. Like any electricaly charged object, plasma produces magnetic fields when it moves As those fields shift, they induce more currents, which in turn produce more fields This tangle of plasma and electric and magnetic effects determines the forms of nearly everything in or above the Sun, such as the bright coronal loops and the dark areas we call sunspots. Everything we see as solar activity is a magnetic field being acted upon by plasma and vise-versa. Both are forever in motion.

WHAT INTERIOR MECHANISMS PRODUCE THE SUN’S MIGHTY MAGNETIC DYNAMO? The magnetic field drives virtually everything on the Sun Sun has opposite north and south magnetic poles like the Earth The Earth’s field is produced by motion of the molten iron in the outer core The Sun’s field is produced by the internal motion of plasma Until recently, imposible to see beneath the photosphere Helioseismology developed – an ultrasound scan on the Sun’s interior Global Oscillation Network Group (GONG) – worldwide array of observation stations positioned 60-degrees apart to observe the Sun 24-hours a day

The idea came about in the 60s – observed that solar surface throbbed with rhythmic oscillations like the skin of a drum Discovery: Much faster rotation at equator than at poles The “shear zone” (a.k.a. – tacholine) between the regions of varying rotations is what is believed to cause the magnetic field. The internal motion stretches and twists the north-south magnetic field lines, wrapping them around the Sun thus adding energy (imagine how energy is stored in a stretched rubber band) Sometimes the powerful twisted field lines become buoyant and rise above the photosphere – these manifest as loops, prominences and sunspots, which are observed on the surface of the Sun

SOLAR FLARE – A sudden eruption of energy on the solar disk, lasting minutes or hours, in which energy and particles are released. A small area above the solar surface suddenly roars to tens of millions of degrees, throwing off a surge of radiation that can cause communication blackouts, disable satellites, or kill a spacewalking astronaut.

CORONAL MASS EJECTION - billions of tons of charged particles escape from the sun’s halo, the corona, at millions of miles per hour. When these behemoth clouds slam into the Earth’s protective magnetosphere, they squash magnetic field lines and dump trillions of watts of power into the Earth’s upper atmosphere. This can overload powerlines, causing massive blackouts, and destroy delicate instruments on anything in Earth’s orbit.

This image was acquired from NASA's Skylab space station on December 19, It shows one of the most spectacular solar flares ever recorded, propelled by magnetic forces, lifting off from the Sun. It spans more than 588,000 km (365,000 miles) of the solar surface. Solar flare -

SOLAR WIND - A tenuous flow of gas and energetic charged particles, mostly protons and electrons (plasma) -- which stream from the Sun; typical solar wind velocities are almost 350 kilometers (217 miles) per second.plasma MAGNETOSPHERE – Outer portion of the Earth’s - or any planet’s atmosphere - in which the magnetic field interacts with the solar wind.

WHAT EXPLAINS FLARES AND THE CORONAL MASS EJECTIONS THAT ARE RESPONSIBLE FOR ELECTRICAL TEMPESTS ON EARTH? HOW CAN THESE STORMS BE PREDICTED? The corona produces the most powerful particle accelerators in the solar system – flares and CMEs Flares expel much of their energy as x-rays and are genrated when electrical currents are suddenly released as one or more magnetic field loops in the corona become strained to the breaking point and snap into a new shape This radiation reaches the earth in 8 minutes and can disrupt radio communications and navigation systems. A small percentage of flares hurl out fast-moving, high-energy protons that can cripple satellites. CMEs often follow flares These massive eruptions of plasma can also occur on their own CMEs take 1-3 days to reach Earth They smash into the Earth’s magnetosphere and deform it – and if conditions right – produce a multi-million ampere ring current in the belts of charged particles that continually circle the Earth.

CMEs are even more threatening to communication satellites than flares and can take out power grids causing power failures. The trigger mechanism for CMEs is not known, therefore not possible to predict With SOHO, et.al., we can see these storms leaving the Sun The magnetic polarity of a CME can change during its journey If the polarity is opposite that of the Earth’s, it does the most damage on impact We can predict with 80-percent accuracy if they will hit the Earth The worst storms often come in the waning years after the solar maximum. The most recent solar max. ended in 2001; the strongest x-ray flare ever observed was in Nov. 2003