1. Solar and Astrophysics Laboratory, Dept. H1‐12, Bldg. 252, Lockheed Martin, 3251 Hanover Street, Palo Alto, California 94304 and California Institute for Physics and Astrophysics, 366 Cambridge Ave., Palo Alto, CA 94306
2. Department of Electrical Engineering, ECS Building, California State University, 1250 Bellflower Blvd., Long Beach, California 90840
3. C‐131 Engineering Quad, Princeton Univ., Princeton, NJ 08544‐5263