Faculty of Science Department of Physics Field Line Resonances in the Earth’s Magnetosphere and Astrophysical Plasmas 1 J. C. Samson

Faculty of Science Department of Physics Brief Outline 2 1.Early Years: (Early theories of FLRs) Dungey 1954, Tamao The Middle Years: ) (Consolidation of FLR model and further observations) Chen and Hasgawa 1974, Greenwald and Walker 1980, Samson 1972 (etc.), Southwood The Later Years: Discrete FLRs, (Cavity and waveguide modes, nonlinear MHD and FLRs, kinetic effects, auroral arcs) Kivelson and Southwood 1985, Wright, Samson et. al. (various including Dobias, Fenrich, Greenwald, Harrold, Rankin, Ruohoniemi, Waters) 4. The Later Years (Astrophysical plasmas) Rezania and Samson 2004 (neutron star magnetospheres) (And, of course, there are many other papers and authors.)

Faculty of Science Department of Physics Tamao 1965 FLRs 3 [See also Southwood, ]

Faculty of Science Department of Physics FLR in Equatorial Plane (Radial E-field) 4 ( Samson, 2011)

Faculty of Science Department of Physics 5 STARE radar observations of N-S electric field ( mHz) in the ionosphere (Greenwald and Walker,1980). FLR radial E-field in Equatorial plane (solid line: amplitude; dashed line: phase) (Samson, 2011). FLR electric fields

Faculty of Science Department of Physics Polarization of 5 mHz FLRs (horizontal plane) UofA Magnetometers 6 Samson, 1972

Faculty of Science Department of Physics Latitude Dependence of Period or Frequency of FLRs 7 Nishida, 1978Samson and Rostoker, 1972 Maximum U Alberta H-component magnetometer data

Faculty of Science Department of Physics CANOPUS Meridian Scan of Auroral Arcs Produced by a FLR 8

Faculty of Science Department of Physics Dispersive Field Line Resonances 9 Trondsen, T. S., L.L. Cogger, and J.C. Samson,, Geophys. Res. Lett., 24, , 1997.

Faculty of Science Department of Physics Observed Discrete Modes in FLRs: SuperDarn data 10

Faculty of Science Department of Physics MHD Waveguide or Cavity Modes 11

Faculty of Science Department of Physics FLRs in Neutron Star Magnetospheres 12 The discovery of quasi-periodic oscillations (QPOs) in low-mass X-ray binaries (LMXBs) has been reported and discussed in recent studies in theoretical and observational astrophysics. The Rossi X-Ray Timing Explorer has observed oscillations in the X-ray flux of about 20 accreting neutron stars. These oscillations are very strong and remarkably coherent with frequencies ranging from » 10 Hz to » 1200 Hz. The kHz frequencies correspond to dynamical time scales at radii of a few tens of kilometers, and are possibly closely related to the Keplerian orbital frequency of matter at the inner disk. Almost all sources have also shown twin spectral peak QPOs in the 500 Hz to 1200 Hz part of the spectrum.

Faculty of Science Department of Physics FLRs, QPOs and X-ray Aurora in Neutron Star Magnetospheres 13 Theoretical model (Rezania and Samson, 2004).

Faculty of Science Department of Physics Summary 14 1.Early Years: (Early theories of FLRs) Impressive achievements and a strong start for future studies of FLRs. 2.The Middle Years: The field reaches maturity, at least for nonlinear MHD models. A variety of instruments has now seen FLRs (radars, magnetometers (on the ground and satellites), optical instruments). 3.The Later Years: There are many solid achievements,including new ideas with kinetic effects and nonlinear MHD, but many puzzles remain, including the sources of discrete modes and auroral arcs. The future looks exciting. 4. The Later Years (Astrophysical plasmas) The universe is before us! (Including FLRs in planetary magnetospheres, astrophysical systems (including stars, neutron stars, and, (could it be?), black holes.)

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