Comment on the polarity of magnetic clouds

The initial description of magnetic clouds by Klein and Burlaga (1982) and the models that have been developed for their representation (e.g., by Goldstein, 1983) are examined. The results show that a definition of the cloud's polarity only in terms of the Bz component of the IMF is not always correct. It is suggested that, for the description polarities of quasi-transverse and quasi-parallel clouds, a combination of directions in the Bz and By components of the IMF should be used.