Pc1 measurements of EMIC waves are not significantly linked to the
acceleration of auroral protons in the cusp.
We present three pieces of observational evidence to conclude that EMIC
waves are not the mechanism responsible for the acceleration of auroral
protons in the polar cusp. It is widely believed that ElectroMagnetic
Ion Cyclotron (EMIC) plasma waves are the mechanism responsible for the
acceleration of auroral protons - however, measurements of auroral
proton precipitation and Pc1 pulsations from Svalbard under the cusp
region indicate that there is no significant link between the two
phenomena. Spectrograph measurements of proton aurora over Svalbard are
studied alongside co-located magnetometer measurements of Pc1
pulsations. No evidence of a link between proton aurora and Pc1 waves
was found by three different methods. Firstly, accelerated protons and
Pc1 pulsations have no coincident occurrence. Secondly, the proton
energy spectrum does not change between Pc1 activity and quiet times.
Finally, no imprint of the EMIC wave is found in periodicity of the
intensity and blue-shift of the proton H-$\alpha$ line,
unlike in flickering electron aurora where intensity fluctuations are
caused by EMIC waves. It may be possible that EMIC waves are causing
acceleration but not propagating down to cause Pc1 pulsations, however
we deem this unlikely. Therefore we conclude that EMIC waves are not the
mechanism responsible for accelerating auroral protons in the cusp.