Almost 30 years ago, I wandered into a small office in the basement of Sterling Hall and met a tall, distinguished gentleman, whom I had been told was the one to see about jobs in plasma physics. I really wasn't interested in plasma physics, but I was a beginning graduate student in need of financial support, and I had been to all the other groups in the Department without success.
I didn't know anything about this "Professor Kerst", but the next five minutes was to launch me on a professional and personal odyssey whose end is yet to come. He listened to my story, and then asked a single question: "Do you know anything about electronics?" Figuring this was not the time for modesty, I said "I'm a whiz at electronics", and he said "You're hired."
As time went on, this initial impression of Don Kerst was greatly reinforced. He was compassionate, direct, always helping people perform to the limit of their capabilities, but most of all, he had a driving desire to understand the world around him. To him, physics was not just a profession, but a way of life. He became much more than my thesis advisor. He was more like a father and mentor.
It would be easy for one as accomplished as Don Kerst to intimidate others, but that wasn't his style. He always treated the graduate students as colleagues. He found merit in even the craziest idea. He built others up, not put them down. He expected the best from people, and we worked hard to live up to his expectations.
He was a generous man. He always gave credit to those who worked for him. At scientific meetings, he would let us give the talks. He seldom put his name on our papers, even though many of the ideas were his. When important people from other laboratories visited, he would have the graduate students show them around and describe the machines and the research.
And the research that we were doing was exciting. Don had returned to Madison in 1962 with an idea for a new plasma confinement device--the toroidal octupole. That device was the one in which plasmas were first tamed, and it revitalized the quest for magnetic fusion energy. Don's leadership and experience helped establish plasma physics as a legitimate scientific discipline.
His love of physics was legendary. Whenever he had a new idea or had figured something out, he had to tell someone. I frequently got phone calls from him early in the morning and listened to what had been on his mind throughout the night. He once had me paged at an airport between flights just to tell me something that he found exciting. And this excitement and thirst for understanding was contagious.
Don also loved the water. Some of my fondest memories of him were of the times we canoed on Lake Mendota or sailed his boat in the Bahamas. He was the consummate captain--confident, commanding, and concerned for detail. But even there, physics was not far from his mind. He would explain how to calculate the hull speed of the boat, or the distance to the horizon, or how to navigate by the stars.
In his later years, Don became interested in ham radio. This was an interest kindled in his childhood by his experiments with spark-gap transmitters. His neighbors would blame him wherever reception was bad on their radios. He also bought a personal computer and spent many--sometimes frustrating--hours trying to learn its intricacies. It was a joy to help him with his radios and computers and to give back a bit of what he so generously gave me.
When Don and Dorothy sold their house in Madison and moved to Florida, he left behind the active research program that he had begun. But his influence continued. Our newest machine includes unusual features that incorporate many of his ideas. He regularly called to inquire about the research. His interest in the program never waned. Nothing made him happier than talking about a new physics problem or result.
This is how I will always remember Don Kerst--friend, mentor, the passionate scientist, and a remarkable human being.
J. C. Sprott