Characterization of ULF pulsations by THEMIS



[1] The THEMIS five-probe constellation was launched in 17 February 2007 to study substorms; however its instrumentation and the alignment at distances <1RE among some of the THEMIS probes, particularly in the first period of its mission, provides unique opportunities to study ULF pulsations in the magnetosphere. In the case study presented, electric and magnetic field fluctuations are identified as field line resonances and their modes of oscillation are discussed. Phase-difference calculations between probes allow estimates of the mode number of the fluctuations. These observations give an excellent source for the verification of model estimates of frequency and polarization of the various modes of field line resonances.