A more stable situation is He3 closet to the axis and Deuterium closer to the border. But what happens it is that colder He3 will be in contact with hotter D. The D+ He3 below 100K is too low, so He3 will just cool without fusion, but if any of them fuses, it will just emit and alpha + proton at very high energies.
So, what will happen is that the He3 layer and D will cool each other and tend to expand adiabatically , given that the plasmoid is mostly opaque to xrays. This will tend to reduce the cross section for D+D. The good side of this it is that the shear between layers of different layers and the plasmoid will last longer and given the conteracting negative pressure to the compression.
