Estimate the temperature needed to achieve the fusion of deuterium to make an alpha particle. The energy required can be estimated from Coulomb's law [use the form E=9x10^9 (Q1Q2 r), using Q=1.6x10^-19 C for a proton, and r=2x10^-15 m for the helium nucleus; the unit for the proportionality constant in Coloumb's law is J*m/C^(2)]