  We present archive Atacama Large Millimeter/Submillimeter Array (ALMA) Band 6
observations of the $^{13}$CO (J=2-1) and $^{12}$CO (J=2-1) molecular line
emission of the protostellar system associated with HH 30. The $^{13}$CO
molecular line shows the accretion disk while the molecular outflow is traced
by the emission of the $^{12}$CO molecular line. We estimated a dynamical mass
for the central object of $0.45\pm0.14$ M$_\odot$, and a mass for the molecular
outflow of $1.83\pm0.19\times10^{-4}$ M$_\odot$. The molecular outflow presents
an internal cavity as well as multiple outflowing shell structures. We
distinguish three different shells with constant expansion ($\sim4-6$ km
s$^{-1}$) and possible rotation signatures ($\leq0.5$ km s$^{-1}$). We find
that the shells can be explained by magnetocentrifugal disk winds with
launching radii $R_\mathrm{launch}\lesssim4$ au and a small magnetic lever arm
$\lambda\sim1.6-1.9$. The multiple shell structure may be the result of
episodic ejections of the material from the accretion disk associated with
three different epochs with dynamical ages of $497\pm15$ yr, $310\pm9$ yr, and
$262\pm11$ yr for the first, second, and third shells, respectively. The
outermost shell was ejected $187\pm17$ yr before the medium shell, while the
medium shell was launched $48\pm14$ yr before the innermost shell. Our
estimations of the linear and angular momentum rates of the outflow as well as
the accretion luminosity are consistent with the expected values if the outflow
of HH 30 is produced by a wide-angle disk wind.

Solar and Stellar Astrophysics;Astrophysics of Galaxies