For a successful operation of a thermonuclear reactor, Lawson's criterion is given by

The correct answer is (C) n$\tau$ T >= 50 * 10^20 keVs/m^3.

• Lawson's criterion defines the conditions required for a thermonuclear fusion reactor to reach net energy gain (ignition), expressed via the fusion triple product:
• $\text{Triple Product}=n{\tau }_{E}T\ge 5\times {10}^{21}{\text{ m}}^{-3}\cdot \text{s}\cdot \text{keV}=50\times {10}^{20}\text{ keV}\cdot {\text{s/m}}^3$$\text{Triple Product}$ = n $\tau$_E T $\ge$ 5 $\times$ 10^{21} $\text{ m}$^{-3} $\cdot$ $\text{s}$ $\cdot$ $\text{keV}$ = 50 $\times$ 10^{20} $\text{ keV}$$\cdot$$\text{s/m}$^3
• Here, $n$ is plasma particle density, $\tau$$\tau$ is energy confinement time, and $T$ is plasma temperature.