  The Parker Solar Probe (PSP) observed an interplanetary coronal mass ejection
(ICME) event during its first orbit around the sun, among many other events.
This event is analyzed by applying a wavelet analysis technique to obtain the
reduced magnetic helicity, cross helicity, and residual energy, the first two
of which are magnetohydrodynamics (MHD) invariants. Our results show that the
ICME, as a large scale magnetic flux rope, possesses high magnetic helicity,
very low cross helicity, and highly negative residual energy, thus pointing to
a magnetic fluctuation dominated structure. Using the same technique, we also
search for small-scale coherent magnetic flux rope structures during the period
from 2018/10/22--2018/11/21, which are intrinsic to quasi-2D MHD turbulence in
the solar wind. Multiple structures with duration between 8 and 300 minutes are
identified from PSP in-situ spacecraft measurements. The location and scales of
these structures are characterized by wavelet spectrograms of the normalized
reduced magnetic helicity, normalized cross helicity and normalized residual
energy. Transport theory suggests that these small-scale magnetic flux ropes
may contribute to the acceleration of charged particles through magnetic
reconnection processes, and the dissipation of these structures may be
important for understanding the coronal heating processes.
