  SU Aurigae is a T Tauri star that was well monitored during the MUSICOS 96
multi-site campaign. We present the results of the spectroscopic analysis of
the circumstellar environment of this star, particularly of the Halpha, Hbeta,
Na I D and He I D3 line profiles. The signatures of modulated outflows and mass
accretion events are analysed, as well as transient spectral features. We
compute the cross-correlation function (CCF) of several pairs of (velocity bins
in) spectral lines to better investigate the profiles' temporal variability. We
found increasing time lags between the variability of He I D3, Na I D and
Hbeta. We propose this may be understood in terms of azimuthal distortion of
the magnetic field lines due to the different rotation rates of the star and
the disk. We find the slightly blueshifted absorption features in Halpha, Hbeta
and Na I D to be anti-correlated with the accretion flow signatures. We propose
that the transient absorption features in the blue wings of Halpha, Hbeta and
Na I D (signatures of mass outflows), and flare brightenings are related to the
disruption of distorted magnetospheric field lines.

Astrophysics