Van Allen Probes EMFISIS Waves
Birthday Chorus 2014-08-28

August 30, 2014, marks the 2nd anniversary of the launch of the twin Van Allen Probes spacecraft. To celebrate, the EMFISIS/Waves team presents a sample of chorus emissions that looks remarkably like a line of birthday candles. The magnitude of the chorus elements in this example is evidently resulting in some artifacts at higher frequencies and the higher frequency elements are likely not real. Nevertheless, the result is to add flames to the candles on the Van Allen Probes birthday cake.

Happy birthday to the Van Allen Probes! We're looking forward to even more exciting new discoveries!

These signals were recorded by the Van Allen Probes A spacecraft EMFISIS Waves instrument on 2014-08-28 beginning about 03:13 UTC. The measurements of three orthogonal magnetic antennas Bu, Bv, and Bw were combined to make the 12-second stereo audio recording.

The video presents a frequency-time spectrogram for the three antennas, with a moving cursor that shows the time position of the audio track. Time advances from left to right along the horizontal axis, frequency ranges from low to high frequencies along the vertical axes, and the amplitude of the signals is color coded with blue indicating weak signals and red indicating strong signals.