To quantitatively control the aspect ratio of hollow glass microspheres(HGMs)for inertial confinement fusion(ICF)targets

a model was developed to describe the relationship between HGM aspect ratios and compositions and pressures of furnace gas

based on the process analysis of transformation mechanism from gel microspheres to HGMs in the drop-tower furnace.Furthermore

the mean diameters and aspect ratios of HGM batches under different compositions and pressures of furnace gas were experimentally investigated.The results showed that the shell-blowing process from the initial molten glass bubble to the resulting liquid HGM could be regulated by the partial pressures of argon gas in the furnace atmosphere

and therefore the diameters and aspect ratios of HGMs could be quantitatively controlled by the partial pressure of argon gas in the furnace atmosphere.However

it was infeasible to produce large-diameter HGMs with target quality by simply reducing the partial pressures of argon gas to zero.To meet the stringent requirements of ICF targets

special furnace gases with enough partial pressures of helium gas must be used to obtain high quality HGMs with good sphericity

surface finish and high yield.Except for the extreme operation conditions of excessively high(>0.08 MPa)or low(<0.01 MPa)partial pressures of argon gas in the furnace atmosphere

the predicted values of the model proposed in this work agreed well with the experimental results.