Fig. 2From: A case study of correspondence between Pc1 activity and ionospheric irregularities at polar latitudesCoherence (panel c), polarization ratio (panel d) and ellipticity (panel e) of the magnetic field horizontal components at MZS on 22 February 2007 between 0200 and 1400 UT. Black contours indicate an \(SNR\left( f \right)\) greater than 3 at MZS (see Fig. 1). Panels a and b show details of 200–400 mHz filtered signals during two 4-min intervalsBack to article page