chapter  3
34 Pages

Measurement of Electric Field and Ion-Related Quantities

ByRonald H. McKnight

MEASUREMENT OF ELECTRIC FIELD AND ION-RELATED QUANTITIES*

Ronald H. McKnight

TABLE OF CONTENTS

I. Introduction 24

II. Definition of Terms 24

III. Measurement of Electric Field and Space Potential 26 A. Electric Field 26 B. Space Potential 30

IV. Measurement of Vertical Current Density 30

V. Measurement of Conductivity 32

VI. Measurement of Net Space Charge Density 36 A. Cage Methods 36 B. Filtration Methods 38

VII. Measurement of Unipolar Ion Density 39

VIII. Measurement of Ion Mobility and Species Identification 41

IX. Errors Associated with External Electric Fields and Off Ground Operation of Instruments 45 A. Effects Due to External Fields 45 B. Space Charge Effects 47

X. Applications of Measurements 48 A. HVDC Transmission Lines 48 B. Biological Exposure Systems 50 C. Room Measurements 51

Acknowledgments 51

References 52

24 Air Ions: Physical and Biological Aspects

I. INTRODUCTION

Measurements of various quantities to describe the electrical characteristics of the atmosphere have been made for many decades by atmospheric scientists using a variety of instruments and measurement techniques. The purpose of this chapter is to describe those techniques which have application in present-day ion-related research. References chosen are representative and it is not intended that they be exhaustive. Summaries, specialized texts," and proceedings of conferences' are excellent sources for more detailed discussions of particular topics and should be consulted by the interested reader.'