Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
The four magnetic arrays of an Apple undulator are schematically represented to highlight the basic topology involved in this undulator concept: array pairs 1–2, 2–3, 3–4 and 4–1 are called neighbouring arrays, while pairs 1–3 and 2–4 are called opposite arrays.
