Unique concurrent observations of whistler mode hiss, chorus, and triggered emissions

We present a unique two hour ground based observation of concurrent magnetospheric hiss, chorus, VLF triggered emissions as well as ELF/VLF signals generated locally by the High Frequency Active Auroral Research Program (HAARP) facility. Eccentricity of observed wave polarization is used as a criteria to identify magnetospheric emissions and estimate their ionospheric exit points. The observations of hiss and chorus in the unique background of coherent HAARP ELF/VLF waves and triggered emissions allows for more accurate characterization of hiss and chorus properties than in typical ground based observations. Eccentricity and azimuth results suggest a moving ionospheric exit point associated with a single ducted path at L~5. The emissions exhibit dynamics in time suggesting an evolution of a magnetospheric source from hiss generation to chorus generation or a moving plasmapause location. We introduce a frequency band-limited autocorrelation method to quantify the relative coherency of the emissions. A range of coherency was observed from high order of coherency in local HAARP transmissions and their echoes to lower coherency in natural chorus and hiss emissions.

[1]  Stephen D. Gedney,et al.  Using Eccentricity to Locate Ionospheric Exit Points of Magnetospheric Whistler Mode Waves , 2018, IEEE Transactions on Geoscience and Remote Sensing.

[2]  Umran S. Inan,et al.  On the occurrence of ground observations of ELF/VLF magnetospheric amplification induced by the HAARP facility , 2011 .

[3]  M. Cohen,et al.  Amplitude and phase of nonlinear magnetospheric wave growth excited by the HAARP HF heater , 2010 .

[4]  Umran S. Inan,et al.  Cross modulation of whistler mode and HF waves above the HAARP ionospheric heater , 2009 .

[5]  B. Tsurutani,et al.  Plasmaspheric hiss properties: Observations from Polar , 2015 .

[6]  R. Raghuram,et al.  A quiet band produced by VLF transmitter signals in the magnetosphere , 1977 .

[7]  N. Meredith,et al.  The unexpected origin of plasmaspheric hiss from discrete chorus emissions , 2008, Nature.

[8]  M. Gołkowski,et al.  Propagation of whistler mode waves with a modulated frequency in the magnetosphere , 2010 .

[9]  Umran S. Inan,et al.  Orientation of the HAARP ELF ionospheric dipole and the auroral electrojet , 2008 .

[10]  Craig A. Kletzing,et al.  Fine structure of plasmaspheric hiss , 2014 .

[11]  H. Matsumoto,et al.  A review of observational, theoretical and numerical studies of VLF triggered emissions , 1991 .

[12]  R. Helliwell,et al.  VLF wave stimulation experiments in the magnetosphere from Siple Station, Antarctica , 1988 .

[13]  Sergei Sazhin,et al.  Whistler diagnostics of magnetospheric parameters: A review , 1992 .

[14]  Stephen D. Gedney,et al.  Multistation observations of the azimuth, polarization, and frequency dependence of ELF/VLF waves generated by electrojet modulation , 2015 .

[15]  Y. Omura,et al.  Theory and simulation of the generation of whistler‐mode chorus , 2008 .

[16]  Koons.  The role of hiss in magnetospheric chorus emissions. Technical report , 1981 .

[17]  Umran S. Inan,et al.  Multistation observations of ELF/VLF whistler mode chorus , 2008 .

[18]  V. Angelopoulos,et al.  An Observation Linking the Origin of Plasmaspheric Hiss to Discrete Chorus Emissions , 2009, Science.

[19]  Umran S. Inan,et al.  Magnetospheric amplification and emission triggering by ELF/VLF waves injected by the 3.6 MW HAARP ionospheric heater , 2008 .

[20]  K. Papadopoulos,et al.  Artificial ducts caused by HF heating of the ionosphere by HAARP , 2012 .

[21]  D. Gurnett,et al.  Transverse dimensions of chorus in the source region , 2003 .

[22]  T. Bell,et al.  Controlled precipitation of radiation belt electrons , 2003 .

[23]  M. Spasojević,et al.  Diurnal dependence of ELF/VLF hiss and its relation to chorus at L = 2.4 , 2009 .

[24]  Richard M. Thorne,et al.  The dual role of ELF/VLF chorus waves in the acceleration and precipitation of radiation belt electrons , 2007 .