Interwoven Space Physics Stories

about the solar wind striking the Earth, the aurora, and the halo around both of the Earth's magnetic poles

Presented bilingually. Click to toggle: Scientific Presentation Plain English

	Top Story: Solar Cycle and the Aurora After the 11-year solar cycle was established in the 18th century, efforts began to find out if the terrestrial environment was affected. The first relationship which seemed clear is that more aurora occur following solar maximum that minimum. We re-examined this question to test a controversial theory of auroral arc formation, with surprising results.

	Story 1: Is the aurora there when no one is looking? The aurora has been studied for centuries by scientists and enjoyed by others for much longer. The northern lights can only be seen at nighttime, but it has always been assumed that, like the stars, the aurora was still there after the sun came out. New research by the auroral particles and images group at JHU/APL shows that aurora which are intense enough to be seen with the unaided eye are in fact comparatively rare when the sun is above the horizon. The northern lights are present much more often when they can be seen (when the sun is down).

	Story 2: Barring the Earth's Halo. Yes, the Earth really does have a halo around its magnetic poles, easily visible from space. It has been suggested, but not widely believed, that an odd effect can bifurcate the halo. The odd result is that the aurora looks like the Greek symbol "theta" when looked at from above by a satellite. Does it really happen? How? New research results give some answers.

	Story 3: The Solar Wind Striking the Earth's Atmosphere. The Earth's magnetic field mostly keeps the solar wind away from the atmosphere. However the magnetic field lines which come out of the Earth from inside the halo -- in the polar regions -- are connected up to the solar wind, allowing the hot solar wind plasma in. New computer simulations are finally doing a good job of representing this complex process.

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