Search Results (4 total)

A theoretical methodology promising improved design of vacuum insulation in high-voltage pulsed-power systems is described. It consists of shaping the electromagnetic fields within the system in such a way that charged particles which can in principle initiate vacuum surface breakdown are deflected away from the insulator surface, and secondary electrons, if emitted, are prevented from restriking the surface. Thus, vacuum surface breakdown is prevented before it is able to develop. Our methodology is presented here by a set of case studies.

We give a dynamical explanation for the localization of the wave function for the one-dimensional hydrogen atom, with the Coulomb singularity, in a high-frequency electric field, which leads to a necessary condition for classical dynamics to be valid. Numerical tests confirm the accuracy of the condition. Our analysis is relevant to the comparison between the classical and quantal dynamics of the kicked rotor and standard map.

Ionization of hydrogen atoms with principal quantum number n=32, 40, and 51-74 by a 9.92-GHz electric field F(t)=z-^ F₀cosωt was studied with a superimposed static electric field F̅ _s=0, 2, 5, and 8 V/cm. The measured field strengths F₀(10%) at which 10% of the atoms were ionized are in excellent agreement with classical calculations in both one and two spatial dimensions. Covering finer detail as well as gross structure of the n dependence of F₀(10%), the agreement supports the application of classical dynamics to the analysis of this strongly perturbed quantum system.

A classical theory gives excellent agreement with the Bayfield-Koch experiment on microwave ionization of Rydberg hydrogen atoms. The time dependence of excitation and ionization is presented, and classical trajectories are divided into four significant categories. The results suggest that nonresonant laser ionization of atoms in states of low quantum number can also take place as a result of extremely high-order processes with large numbers of intermediate states of excitation.