Celebrating the Life and Career of Joel Fajans

We reflect on the distinguished scientific career of Joel Fajans, marked by numerous contributions to non-neutral plasma physics and its applications. From his early doctoral work on free electron lasers at M. I. T. to his postdoctoral research with John Malmberg on trapped non-neutral plasmas, and continuing through his group leadership at U. C. Berkeley, Joel has significantly advanced this rich area of plasma physics. His career has also touched on a breadth of other topics, including the physics of bicyling – a personal passion. His interest in plasma transport and instability phenomena in non-uniform fields led to his pivotal proposal of octupole magnetic traps for capturing antihydrogen atoms—an innovation that became foundational to the ALPHA experiment and enabled the first atomic physics studies of antihydrogen. Joel's direct involvement in the experiment defined his later career, including deep insights into the plasma physics challenges of producing antihydrogen from trapped charged particles and devising ingenious experiments, including the balance measurement used by ALPHA-g to achieve the first direct observation of antimatter’s behavior in a gravitational field. Beyond his scientific achievements, Joel had a lasting impact on colleagues and students alike—both professionally and personally—through his keen intellect, infectious enthusiasm, and sharp sense of humor.