GC: n
CT: Using data from a NASA satellite, scientists have discovered a massive particle accelerator in the heart of one of the harshest regions of near-Earth space, a region of super-energetic, charged particles surrounding the globe and known as the Van Allen radiation belts.
New results from NASA’s Van Allen Probes show the acceleration energy is in the belts themselves. Local bumps of energy kick particles inside the belts to ever-faster speeds, much like a well-timed push on a moving swing. Knowing the location of the acceleration within the radiation belts will help scientists improve predictions of space weather, which can be hazardous to satellites near Earth. The results were published Thursday in the journal Science.
S: NASA – https://www.nasa.gov/press/2013/july/nasa-mission-discovers-particle-accelerator-in-heart-of-van-allen-radiation-belts/#.WFL_NcQrLIU (last access: 15 December 2016)
N: 1. particle (n): Late 14c., “small part or division of a whole, minute portion of matter,” from Latin particula “little bit or part, grain, jot,” diminutive of pars. Particle physics attested from 1969. In construction, particle board, 1957, is so called because it is made from chips and shavings of wood.
accelerator (n): 1610s, “a hastener,” from Latin accelerator, agent noun from accelerare “to hasten; make haste”. Motor vehicle sense of “engine speed modulation apparatus” is from 1900; particle physics sense is from 1931.
2. A device for imparting kinetic energy to charged particles.
3. The Large Hadron Collider (LHC) is the world’s largest and most powerful particle accelerator. It first started up on 10 September 2008, and remains the latest addition to CERN’s accelerator complex. The LHC consists of a 27-kilometre ring of superconducting magnets with a number of accelerating structures to boost the energy of the particles along the way.
4. Inside the accelerator, two high-energy particle beams travel at close to the speed of light before they are made to collide. The beams travel in opposite directions in separate beam pipes – two tubes kept at ultrahigh vacuum. They are guided around the accelerator ring by a strong magnetic field maintained by superconducting electromagnets. The electromagnets are built from coils of special electric cable that operates in a superconducting state, efficiently conducting electricity without resistance or loss of energy. This requires chilling the magnets to ‑271.3°C – a temperature colder than outer space. For this reason, much of the accelerator is connected to a distribution system of liquid helium, which cools the magnets, as well as to other supply services.
5. Thousands of magnets of different varieties and sizes are used to direct the beams around the accelerator. These include 1232 dipole magnets 15 metres in length which bend the beams, and 392 quadrupole magnets, each 5–7 metres long, which focus the beams. Just prior to collision, another type of magnet is used to “squeeze” the particles closer together to increase the chances of collisions. The particles are so tiny that the task of making them collide is akin to firing two needles 10 kilometres apart with such precision that they meet halfway.
S: 1. OED – http://goo.gl/AVN70D; http://goo.gl/lDLLw1 (last access: 16 December 2016). 2. TERMIUM PLUS – http://goo.gl/lvOsFw (last access: 16 December 2016). 3 to 5. CERN – http://home.cern/topics/large-hadron-collider (last access: 16 December 2016).
SYN: accelerator, atom smasher.
S: TERMIUM PLUS – http://goo.gl/lvOsFw (last access: 16 December 2016)
