Fast Spacecraft Discovery : invisible aurora

An invisible aurora exists as a companion to the familiars visible aurora also known as aurora borealis, or the northern lights, in Northern Hemisphere and the aurora austral is (southern lights) in Southern Hemisphere. The researchers using NASA’s Fast Aurora Snapshot (FAST) Spacecraft established the presence of an invisible aurora by consistently detecting upward flow of electrons interspersed with the downward flowing electrons that produces the visible aurora. The discovery provides first detailed picture of how the aurora and its inverted comp[anion functions together to complete a huge electric circuits in the magnetosphere, which is that region of space where electrically charged particles are controlled by the Earth’s intrinsic (complicated network of passages, intricacies and talents) magnetic field.

The spacecraft’s passages through the electrified auroras regions also provide the best explanation, yet as to how they turn the Earth into a giant radio-transmitter capable of broadcasting  billions of watts of high frequency of radio waves into space. The theory grants new insight into how natural radio transmissions are generated through out the solar system and the cosmos.” The researchers had some previous indicators that the invisible aurora existed, but earlier spacecrafts provided only isolated observations of its presence.” Said Dr Robert Pfaff, FAST Project scientist at NASA’s Goddard Space Flight Center, visible aurora occur when electrons are accelerated by electric fields, the earth’s magnetosphere down along with nearly vertical magnetic field line of Polar region into the upper atmosphere. Aurora light is emitted when the energetic electrons cullied with the neutral atmosphere about 60 – 180 miles ( 100 – 300 kilometers) above the earth’s surface. They create haunting multicolored displays as they crash into atmospheric particles, often appearing as shifting curtains of light from the ground. The invisible magnetic field lines converge as they approach the Earth’s upper atmosphere at polar region, forming a funnel or nozzle shape. FAT data have established that electric fields oriented parallel to these magnetic field lines accelerated the auroral electrons, in much the same way as water is accelerated when passing through the nozzle.

The idea of parallel electric field was proposed over 50 years ago by Nobel Laureate, Hans Alfven of Sweden. Although ridiculed at the time as electric field directed this way were believed the “short out”, when oriented along the highly conducting magnetic field lines, observations gathered in space such as those from FAST satellite, as well as recent theoretical advances, have clearly shown that such processes produce the aurora and may indeed be widespread in nature. Furthermore the FAST data show that the direction of such electric fields are reversed in case where they accelerate electrons up out of the ionosphere to produce the newly discovered invisible aurora. The new type of aurora also known as the inverse or black aurora, is visible because the accelerated electrons are above most of the faint, upper atmosphere by the time they reach speeds that are sufficient to allow the atmospheric atoms and molecules to glow via collisions with the electrons.

In this fashion the upward moving electrons complete the electrical circuit returning current to the distant magnetosphere. The controversial parallel electric field are also directly linked to intense radio emission from the auroral regions, called auroral kilometer radiation, according to the than observation from FAST . The parallel electric fields power a process that generates radio emission called the Electron Cyclotron Laser, which is like natural laser except at radio frequencies. This powerful radio emission, generally at several hundred kilohertz to few megahertz, is not detected on the ground because it is blocked by the Earth’s upper atmosphere (ionosphere) . 

Key to the discovery are the new high resolution electrostatic detectors abroad FAST called “Top Hats” designed and built by Dr Charles Carlson, at the University of California, Berkley, such top hat detectors can sample incoming electrons over a 360 degree field of view with unprecedented time resolution of just a few milliseconds for complete distribution unlike earlier detectors with limited field of view, the FAST energetic particle detectors can continuously sample rapidly moving electricity charged particles in all directions, independent of the satellite’s spin, Dr. Carlson was also the Principal Investigator of the FAST Spacecraft.