ON THE IMPACT OF HIGH-ENERGY HELIUM PLASMA ION FLOW ON TUNGSTEN NANOSTRUCTURE

The processes of plasma formation from helium bubbles-containing tungsten nanofibers when exposed to energy and particle flux from helium plasma under conditions of near-wall potential increased to hundreds of volts, when spontaneous initiation of explosive electron emission bursts is observed, have been considered. It is shown that the development of initiation models under external influence of energy and particle flux requires consideration of nanofibers heterophase structure. Using molecular dynamics method, atomistic modeling of interaction between an incident high-energy helium atom (100-500 eV) with an ensemble of helium atoms in a nanoscale bubble with solid-state of nanofibers heterophase structure 1029 m–3, retained in the near-surface tungsten layer, was performed. The energy relaxation time in the heterophase system of a nanobubble in tungsten was obtained, amounting to several picoseconds. It is shown that at incident particle energies of hundreds of electronvolts, overheating of near-surface nanobubbles is possible, leading to their explosion within times of about 10 ps. Such energy is comparable to the total energy of nanobubble particles, and at such near-wall potential, spontaneous initiations of explosive electron emission bursts are observed.