Francisco J. Higuera

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  • F J Higuera
  • 2003
An analysis is carried out of the electric field-induced evaporation of ions from the surface of a polar liquid that is being electrosprayed in a vacuum. The high-field cone-to-jet transition region of the electrospray, where ion evaporation occurs, is studied taking advantage of its small size and neglecting the inertia of the liquid and the space charge(More)
An asymptotic analysis of the Gunn effect in two-dimensional samples of bulk n GaAs with circular contacts is presented. A moving pulse far from contacts is approximated by a moving free boundary separating regions where the electric potential solves a Laplace equation with subsidiary boundary conditions. The dynamical condition for the motion of the free(More)
The equations describing the rst two terms of an asymptotic expansion of the solution of the planar turbulent mixing layer for values of the velocity ratio close to one are obtained. The rst term of this expansion is the solution of the well-known time-evolving problem and the second, which includes the eects of the increase of the turbulence scales in the(More)
The Kroemer model for the Gunn effect in a circular geometry (Corbino disks) has been numerically solved. The results have been interpreted by means of asymptotic calculations. Above a certain onset dc voltage bias, axisymmetric pulses of the electric field are periodically shed by an inner circular cathode. These pulses decay as they move towards the outer(More)
  • F J Higuera
  • 2004
A simple model is proposed for the flow around the apex of a meniscus of a liquid undergoing ion evaporation in a vacuum under the action of a high electric field. The model includes a simplified description of the effect of the space charge surrounding the evaporating surface, and the idealizations that ion evaporation occurs at a constant surface field(More)
  • F J Higuera
  • 2008
Numerical computations and order-of-magnitude estimates are used to describe the time evolution of a drop of a very viscous liquid of finite electrical conductivity attached to a metallic plate which is suddenly subject to a uniform electric field. Under the action of the electric stresses induced at its surface, the drop elongates in the direction of the(More)
  • F J Higuera
  • 2008
A simple model of the transfer of charge and ion evaporation in the meniscus of an ionic-liquid ion source working in the purely ionic regime is proposed on the basis of order-of-magnitude estimates which show that, in this regime, (i) the flow in the meniscus is dominated by the viscosity of the liquid and is affected very little by the mass flux(More)