Helicons in uniform fields. I. Wave diagnostics with hodograms
| Autor: | R. L. Stenzel, J. M. Urrutia |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences Whistler Field (physics) Plane wave Condensed Matter Physics Wave equation Plasma oscillation 01 natural sciences 010305 fluids & plasmas Magnetic field Computational physics Helicon Physics::Plasma Physics 0103 physical sciences Cylindrical coordinate system 0105 earth and related environmental sciences |
| Zdroj: | Physics of Plasmas. 25:032111 |
| ISSN: | 1089-7674 1070-664X |
| DOI: | 10.1063/1.5017625 |
| Popis: | The wave equation for whistler waves is well known and has been solved in Cartesian and cylindrical coordinates, yielding plane waves and cylindrical waves. In space plasmas, waves are usually assumed to be plane waves; in small laboratory plasmas, they are often assumed to be cylindrical “helicon” eigenmodes. Experimental observations fall in between both models. Real waves are usually bounded and may rotate like helicons. Such helicons are studied experimentally in a large laboratory plasma which is essentially a uniform, unbounded plasma. The waves are excited by loop antennas whose properties determine the field rotation and transverse dimensions. Both m = 0 and m = 1 helicon modes are produced and analyzed by measuring the wave magnetic field in three dimensional space and time. From Ampere's law and Ohm's law, the current density and electric field vectors are obtained. Hodograms for these vectors are produced. The sign ambiguity of the hodogram normal with respect to the direction of wave propagati... |
| Databáze: | OpenAIRE |
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