Scientists at the University of California, Los Angeles introduce novel query on a curious cosmic phenomenon known every bit "whistlers" -- real depression frequency packets of radio waves that race along magnetic plain lines. This first-of-its-kind study, appearing inwards the Physics of Plasmas, from AIP Publishing, provides novel insights into the nature of whistlers as well as infinite plasmas -- regions of energized particles trapped past times Earth's magnetic fields. These studies could i hateful solar daytime assistance inwards the evolution of practical plasma technologies amongst magnetic fields, including spacecraft thrusters that purpose charged particles every bit fuel.
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| Scientists at the University of California, Los Angeles introduce query on a curious cosmic phenomenon known every bit "whistlers" -- real depression frequency packets of radio waves that race along magnetic plain lines. Appearing inwards the Physics of Plasmas, the written report provides novel insights into the nature of whistlers as well as infinite plasmas as well as could i hateful solar daytime assistance in the evolution of practical plasma technologies amongst magnetic fields, including spacecraft thrusters that use charged particles every bit fuel. This ikon shows the increment of a whistler trend amongst round down stage front as well as cross-field propagation [Credit: Reiner Stenzel as well as Manuel Urrutia] |
Whistler waves were commencement detected inwards the early on 1900s. They were flora to come upwards from lightning interacting amongst Earth's magnetic fields. As they traveled through Earth's ionosphere as well as magnetosphere, whistlers amongst depression tones propagate to a greater extent than tardily than the higher frequency whistlers. As a result, uncomplicated radio receivers were used to psyche to the radio waves, as well as the falling pitch sounded similar a whistle.
Stenzel as well as his co-author, Manuel Urrutia, studied the growth, propagation as well as decay of whistler waves inwards nonuniform magnetic fields inwards their laboratory. They discovered that these waves behaved differently than predicted past times an 80-year-old theory.
These laboratory studies involved creating whistler waves amongst magnetic antennas within a plasma-filled chamber. The researchers hence studied the deportment as well as propagation of these waves inwards 3D infinite amongst a movable probe. This enabled the squad to written report how these waves propagate through 3D infinite every bit a component of time. They could besides written report the waves nether a multifariousness of conditions, including how they deport when exposed to both lead as well as round down magnetic plain lines as well as magnetic zippo points -- regions where at that topographic point was no plain at all.
"Our laboratory experiments break three-dimensional moving ridge properties inwards ways that only cannot hold out obtained from observations inwards space," said Stenzel. "This enabled us to written report continuous waves every bit good every bit the increment as well as decay of waves amongst amazing detail. This produced unexpected discoveries of moving ridge reflections as well as of cylindrical whistler modes."
Whistler waves are considered a shape of helicon waves, or low-frequency electromagnetic waves that locomote inwards a corkscrewlike, or helixlike, pattern. When helicons interact amongst plasmas, they exert a pressure level as well as torque on the electrons.
The researchers believe that ameliorate agreement these properties could someday Pb to the pattern of plasma thrusters for infinite vehicles. These thrusters purpose electricity to propel plasma to extremely high speeds, faster than a chemic rocket.
Source: American Institute of Physics [August 14, 2018]
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