David N Walker

Title: Innovations by David N Walker

Introduction

David N Walker is a notable inventor based in Arlington, VA (US). He has made significant contributions to the field of plasma diagnostics, holding 2 patents that showcase his innovative approach to understanding plasma parameters.

Latest Patents

One of his latest patents is the "LC resonance probe for determining local plasma density." This apparatus and method are designed to determine plasma parameters such as plasma electron density (n). The probe apparatus includes an LC resonance probe comprising an inductive element and a capacitive element connected in series. The capacitive element can take various forms, including a parallel plate capacitor, a cylindrical capacitor, or a spherical capacitor. The configuration of the probe gives it a characteristic resonance frequency, which can be determined by a circuit analysis device. When placed in a plasma, the probe exhibits a new resonance frequency, which differs from the original due to the dielectric constant of the plasma. This difference in resonance frequencies can be utilized to determine plasma density (n).

Another significant patent is the "RF probe technique for determining plasma potential." In this method, an RF probe is placed within a plasma, and an RF signal from a network analyzer is applied with a given DC bias voltage. The frequency applied is less than the plasma frequency, ensuring it is not in the resonant absorption range typically used to determine electron density. Bias voltages are applied in a series of steps that include the plasma potential. A local minimum in the real part of the plasma's complex impedance occurs where the applied bias voltage equals the plasma potential. The plasma potential can be determined by analyzing the first derivative of the impedance with respect to the bias voltage.

Career Highlights

David N Walker works for the USA as represented by the Secretary of the Navy. His work focuses on advancing the understanding of plasma behavior and its applications in various fields.

Collaborations

He has collaborated with notable coworkers, including Richard F Fernsler and David D Blackwell, contributing to the advancement of plasma diagnostics.

Conclusion

David N Walker's innovative patents and contributions to plasma diagnostics highlight his significant role in advancing scientific understanding in this field. His work continues to influence research and applications related to plasma technology.