  We propose a modified definition of the jet charge, the "dynamic jet charge",
where the constant jet momentum fraction weighting parameter, $\kappa$, in the
standard jet charge definition is generalized to be a function of a dynamical
property of the jet or the individual jet constituents. The dynamic jet charge
can complement analyses based on the standard definition and give improved
discrimination between quark and gluon initiated jets and between jets
initiated by different quark flavors. We focus on the specific scenario where
each hadron in the jet contributes to the dynamic jet charge with a
$\kappa$-value dynamically determined by its jet momentum fraction. The
corresponding dynamic jet charge distributions have qualitatively distinct
features and are typically characterized by a multiple peak structure. For
proton-proton collisions, compared to the standard jet charge, the dynamic jet
charge gives significantly improved discrimination between quark and gluon
initiated jets and comparable discrimination between $u$- and $d$-quark
initiated jets. In Pythia simulations of heavy ion collisions, the dynamic jet
charge is found to have higher jet discrimination power compared to the
standard jet charge, remaining robust against the increased contamination from
underlying event. We also present phenomenological applications of the dynamic
jet charge to probe nuclear flavor structure.
