  In flare-relevant current sheets, tearing instability may trigger explosive
reconnection and plasmoid formation. We explore how the thermal and tearing
modes reinforce each other in the fragmentation of a current sheet in the solar
corona through an explosive reconnection process, characterized by the
formation of plasmoids which interact and trap condensing plasma. We use a
resistive magnetohydrodynamic (MHD) simulation of a 2D current layer,
incorporating the non-adiabatic effects of optically thin radiative energy loss
and background heating using \texttt{MPI-AMRVAC}. Our parametric survey
explores different resistivities and plasma-$\beta$ to quantify the instability
growth rate in the linear and nonlinear regimes. We notice that for
dimensionless resistivity values within $10^{-4} - 5 \times 10^{-3}$, we get
explosive behavior where thermal instability and tearing behavior reinforce
each other. This is clearly below the usual critical Lundquist number range of
pure resistive explosive plasmoid formation. The non-linear growth rates follow
weak power-law dependency with resistivity. The fragmentation of the current
sheet and the formation of the plasmoids in the nonlinear phase of the
evolution due to the thermal and tearing instabilities are obtained. The
formation of plasmoids is noticed for the Lundquist number ($S_L$) range $4.6
\times 10^3 - 2.34 \times 10^5$. We quantify the temporal variation of the
plasmoid numbers and the density filling factor of the plasmoids for different
physical conditions. We also find that the maximum plasmoid numbers scale as
$S_L^{0.223}$. Within the nonlinearly coalescing plasmoid chains, localized
cool condensations gather, realizing density and temperature contrasts similar
to coronal rain or prominences.
