  We take low-amplitude, long period variable (LA-LPV) candidates in Gaia DR3
as tracers of the kinematics and dynamics of the Milky Way bar. LA-LPVs, like
other LPVs, have high luminosities and follow a tight period-luminosity
relation, but unlike e.g. Mira variables, their radial velocity measurements
are reliable due to their smaller pulsation amplitudes. We supplement the Gaia
astrometric and radial velocity measurements with distance moduli assigned
using a period-luminosity relation to acquire full 6D phase space information.
The assigned distances are validated by comparing to geometric distances and
StarHorse distances, which shows biases less than $\sim5\%$. Our sample
provides an unprecedented panoramic picture of the inner Galaxy with minimal
selection function effects. We map the kinematics of the inner Milky Way and
find a significant kinematic signature corresponding to the Galactic bar. We
measure the pattern speed of the Galactic bar using the continuity equation and
find $\Omega_{\rm b}=34.1\pm2.4$ km s$^{-1}$ kpc$^{-1}$. We develop a simple,
robust and model-independent method to measure the dynamical length of the bar
using only kinematics and find $R_{\rm b}\sim4.0$ kpc. We validate both
measurements using N-body simulations. Assuming knowledge of the gravitational
potential of the inner Milky Way, we analyse the orbital structure of the
Galactic bar using orbital frequency ratios. The $x_1$ orbits are the dominant
bar-supporting orbital family in our sample. Amongst the selected bar stars,
the $x_1 v_1$ or "banana" orbits constitute a larger fraction ($\sim 15\%$)
than other orbital families in the bar, implying that they are the dominant
family contributing to the Galactic X-shape, although contributions from other
orbital families are present.
