  Time integrated spectroscopic measurements are carried out to characterize
transient plasma stream produced in a coaxial pulsed plasma accelerator. This
method allows the estimation of different plasma parameters and its evolution
with time. It also provides information on the existence of different excited
states from the spectral emissions of plasma. Using Argon as the discharge
medium, the electron density estimated from Stark broadened line profiles gives
a peak value $\sim 5 \times 10^{21} m^{-3}$ at a discharge voltage of 15 kV and
the flow velocity of the plasma stream is measured to be $\sim (22 + 5)$ Km
using Doppler shift method. Assuming p-LTE model, the electron excitation
temperature is found to be $\sim 0.88$ eV using Boltzmann plot method. A
temporal evolution of the plasma stream and its characteristic variation is
studied from a time of $50 \mu s-300 \mu s$ in steps of $50 \mu s$ by adjusting
delay time in the triggering. Analysis of different spectral lines shows the
existence of some metastable states of Ar II having a long lifetime. The
evolution of different Ar II transitions to metastable and non-metastable lower
levels is observed for different time frame. The temporal evolution study shows
a decrease in electron density from $1.96 \times 10^{21} m^{-3}$ to $1.23
\times 10^{20} m^{-3}$ at $300 \mu s$ after the initiation of plasma formation.
A decrease in excitation temperature from 0.86 eV to 0.72 eV is observed till
$250 \mu s$ and then again rises to 0.77 eV at $300 \mu s$
