"The difference in location between magnetic north and true north is called the magnetic deviation; not only is the gap getting bigger, it is shifting at an increasing rate. Prior to 1994, it was estimated that the magnetic north pole was moving at about 10 km a year, but since 2001 this has increased to around 65 km a year.
Pole reversals are a natural phenomenon, evidence of which comes from the ocean floor...sediments reveal that over the last 200 million years the poles have reversed, on average, about once every 200,000–300,000 years. Reversals are a slow process and do not happen with any regularity. Nevertheless, the last time this happened was about 780,000 years ago, so we are now overdue for a reversal."
NASA | THEMIS Discoveries:
(0:57) [Narrator] The Sun has a magnetic field of its own as well, which the solar wind carries outwards towards Earth. And the THEMIS Spacecraft fleet recently observed that 20 times more solar particles get into the Earth's magnetosphere when the Sun's magnetic field aligns with that of the Earth than when they are pointed in opposite directions.
THEMIS was launched on February 17th, 2007 and consists of a series of five nearly identical spacecraft. Now, after it's seventh year in space, THEMIS has yielded data which has led to several papers furthering our understanding of Earth's magnetosphere and its connection to the Sun:
"Another group has a paper in print in 2013 based on 2008 data from the five THEMIS spacecraft in conjunction with three of NOAA's GOES (Geostationary Operational Environmental Satellites) spacecraft, and the ESA/NASA Cluster mission. Led by Michael Hartinger at the University of Michigan in Ann Arbor, this group compared observations at the bow shock where the supersonic solar wind brakes to flow around the magnetosphere to what happens inside the magnetosphere. They found that instabilities drive perturbations in the solar wind particles streaming towards the bow shock and that these perturbations can be correlated with another type of magnetized wave – ULF (ultra low frequency) waves - inside the magnetosphere. ULF waves, in turn, are thought to be important for changes in the radiation belts."
"A third interesting science paper from THEMIS's sixth year focused on features originating even further upstream in the solar wind. Led by Galina Korotova at IZMIRAN in Troitsk, Russia, this work made use of THEMIS and GOES data to observe the magnetosphere boundary, the magnetopause. The researchers addressed how seemingly small perturbations in the solar wind can have large effects near Earth. Wave-particle interactions in the solar wind in the turbulent region upstream from the bow shock act as a gate valve, dramatically changing the bow shock orientation and strength directly in front of Earth, an area that depends critically on the magnetic field orientation. The extreme bow shock variations cause undulations throughout the magnetopause, which, launch pressure perturbations that may in turn energize particles in the Van Allen radiation belts."
Some of the key notes of this particular presentation are:
-Every new cycle the sun changes the polarity (direction) of its magnetic fields. The solar wind carries magnetic field from the sun to the magnetosphere. Solar Cycle 24 will bring mostly north-south CMEs.
-These will first bring plasma into the magnetosphere (northern part) and then energise it (southern part) stronger storms are expected because the plasma in the magnetosphere acts like a fuel for the storm.
-THEMIS observes a large breach in Earth's magnetic shield that allows solar particles to enter at a large rate. The magnetic field drapes over the magnetosphere and connects to the Earth's field above the north pole.
-About a minute later it connects with the Earth's field over the south pole: The solar wind field line has now become one of Earth's and the plasma that came with it is in the magnetosphere.
-Contrary to common belief and to many scientists' surprise this breach occurs when the magnetic fields from the Sun and the Earth align. Previously it was thought that more particles enter when the fields are in opposite directions.
RE: 'How to Watch the Sun' - (30:27) It was 2008 when NASA began describing these 'magnetic portals,' this topic in general is for advanced viewers, but think of the connection acting like a wire between the electromagnetic bodies: the Earth and the Sun.
(30:39) And if that portal is surged by a Flare or a Coronal Mass Ejection, then it is possible that this electromagnetic connection between Earth and the Sun might allow the particles to be accelerated to the Earth so quickly...