Polarization analysis of the magnetic field for the time interval 07:00-14:00 UT on 2016 February 19. From top to bottom, panel a: 3D waveforms of the background magnetic field and its modulus, low-pass filtered at 2 mHz. Panel b: spectrogram of the magnitude-squared total magnetic field. Panel c: polarization ellipticity of the magnetic field vector. Panel d: angle θ_k between thewave vector and the background magnetic field, in degrees. The wave vector is only drawn for a sufficient degree of polarization (DOP > 0.6) and planarity (>0.6). Panel e: degree of polarization of the magnetic field vector. Panel f: planarity of the wave vector. The 20-min time intervals used to compute Fig. 3 are shown as horizontal solid lines below the time tags, using the same color code.