The Sun's Magnetic Field
The electric currents in the Sun generate a complex magnetic field with extends out into interplanetary space to form the interplanetary magnetic field. As the Sun's magnetic field is carried out through the solar system by the solar wind, the Sun is rotating. Its rotation winds up the magnetic field into a large rotating spiral, known as the Parker spiral, named after the scientist who first described it.
In the image above, it's easy to see why the neutral current sheet is often called the "ballerina skirt". The Parker spiral is indicated by the arrows. Image is courtesy of J. Jokipii, University of Arizona.
The magnetic field is primarily directed outward from the Sun in one of its hemispheres, and inward in the other. This causes opposite magnetic field directions in the Parker spiral. The thin layer between the different field directions is described as the neutral current sheet. Since this dividing line between the outward and inward field directions is not exactly on the solar equator, the rotation of the Sun causes the current sheet to become "wavy", and this waviness is carried out into interplanetary space by the solar wind. In addition, every eleven years the entire magnetic field of the Sun "flips" -- the north magnetic pole of the Sun becomes the south, and vice versa. The flip takes place at solar maximum. The Sun's Magnetic Field in the News:
April 6, 2012: Mysteries
of the sun...explained in video -- NASA
March 3, 2012: Another tail for Comet Garradd -- APOD February 28, 2012: Mysterious electron acceleration explained -- Science Daily February 25, 2012: Plasmas torn apart -- Caltech January 18, 2012: SDO helps measure magnetic fields on the sun's surface -- NASA July 19, 2011: Two videos of the sun -- Bad Astronomy Blog July 14, 2011: New ways to measure magnetism around the sun -- NASA June 16, 2011: Scientists prove existence of 'magnetic ropes' that cause solar storms -- Science Daily June 9, 2011: A big surprise from the edge of the solar system -- ScienceCast -- Science@NASA June 9, 2011: Magnetic bubbles at the edge of the solar system -- Astrobiology May 2, 2011: Plasmoids and sheaths mean success or failure for solar eruptions -- Science Daily February 24, 2011: Solar experts detect waves in giant magnetic holes the size of the UK -- Eurekalert February 11, 2011: SDO celebrates one year anniversary -- NASA January 10, 2011: New insights into sun's photosphere reported by NJIT researcher at Big Bear -- Eurekalert December 1, 2010: Solar observation mission celebrates 15 years -- NASA September 3, 2010: NASA's magnetospheric mission passes major milestone -- NASA September 2, 2010: The sun's magnetic field warps its environment -- Physics World July 30, 2010: Taking a shot at the sun -- NASA July 24, 2010: First light for Solar Dynamics Observatory -- Nature July 9, 2010: Solar Dynamics Observatory (SDO) captures profile of arcing active solar region -- NASA June 29, 2010: NASA retires TRACE spacecraft after highly successful mission -- NASA June 28, 2010: Current sheets as intermittent structures: ACE/MAG observations -- ACE News June 19, 2010: Music of the sun recorded by scientists -- Telegraph April 21, 2010: NASA's new eye on the Sun delivers stunning first images -- NASA April 12, 2010: Magnetic 'ropes' tie down solar eruptions -- Astronomy January 26, 2010: A flare for forecasting: Sun seismology points to better solar weather predictions -- Scientific American January 22, 2010: National Science Foundation selects National Solar Observatory to build world's largest solar telescope -- Astronomy.com January 13, 2010: Giant magnetic loop sweeps through space between stellar pair -- NRAO November 11, 2009: A bubbling ball of gas -- Eurekalert November 2, 2009: Solar winds triggered by magnetic fields -- Eurekalert August 10, 2009: The violent youth of solar proxies steer course of genesis of life -- IAU June 23, 2009: Magnetic field on bright star Vega -- Astronomy & Astrophysics April 25, 2009: Space missions to visit the Sun -- UK Telegraph January 8, 2009: Magnetic fields could reveal exoplanets -- Physics World October 30, 2008: Magnetic portals connect Sun and Earth -- Science@NASA June 10, 2008: NASA plans to visit the sun -- Science@NASA June 3, 2008: Giant "tornadoes" seen erupting from the sun -- National Geographic May 28, 2008: Plasma twisters seen on the sun -- Nature May 27, 2008: Cartwheel coronal mass ejection -- Science@NASA April 2, 2008: Hinode: Source of the slow solar wind and superhot flares -- ESA March 20, 2008: Science with the solar space observatory Hinode -- Astronomy & Astrophysics March 18, 2008: STEREO: The sun's corona unraveled in 3D -- Sky & Telescope February 26, 2008: Sun-like star flips its magnetic field like our sun: First observation -- Science Daily February 22, 2008: International solar mission to end following stellar performance -- NASA February 13, 2008: Sun-like star flips its magnetic field -- Astronomy.com January 14, 2008: Ulysses spacecraft flies over Sun's north pole -- NASA JPL January 7, 2008: 'Maverick' sunspot heralds new solar cycle -- New Scientist January 2, 2008: Third instrument for NASA's Solar Dynamics Observatory arrives at Goddard -- NASA GSFC November 28, 2007: Odd little star has magnetic personality -- Gemini Observatory November 19, 2007: An extended magnetic reconnection X-line in the solar wind -- ACE News November 16, 2007: Solar Dynamics Observatory instrument to peer inside the Sun arrives at Goddard -- NASA GSFC November 6, 2007: An X class flare region on the Sun -- APOD October 24, 2007: Solar telescope soars into sky on jumbo-jet-sized balloon -- Science Daily August 31, 2007: Scientists find elusive waves in Sun's corona -- Science Daily August 30, 2007: Scientists find elusive waves in solar corona -- NSF July 1, 2007: XMM-Newton reveals X-rays from gas streams around young stars -- Science Daily June 5, 2007: Hinode helps predict solar activity -- Astronomy.com June 1, 2007: XMM-Newson deciphers the magnetic physics around forming stars -- Science Daily June 1, 2007: Pioneering 3D view of near-Earth magnetic 'dance' -- Science Daily June 1, 2007: Secrets of the Sun's sizzling corona -- Australian Broadcasting Company March 22, 2007: Hinode studies the Sun -- Astronomy.com February 7, 2007: South pole flyby -- Science@NASA Click on images above to
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