Dennis W. Mueller, Ph.D.

Dr. Dennis Mueller, 79, of Hopewell, New Jersey, passed away peacefully in his home on June 22, 2026. Born on August 2, 1946, in Moline, Illinois, Dennis led an extraordinary life marked by intellectual achievement, professional excellence, and a deep love for his family and passions.

Dennis's academic journey began at MacMurray College in Jacksonville, Illinois, where he found a sense of belonging that remained with him throughout his life. He went on to earn a master's degree and Ph.D. in nuclear physics from Michigan State University in East Lansing, Michigan. His dedication to the pursuit of knowledge laid the foundation for a remarkable career that spanned over four decades.

As a principal research physicist at Princeton Plasma Physics Laboratory, Dennis was at the forefront of groundbreaking research in controlled thermonuclear fusion. His work involved measuring the temperature of plasmas ten times hotter than the sun and determining methods to control them. Dennis collaborated internationally on the operation of tokamaks in Europe, Korea, and China, leaving an indelible mark on the scientific community and contributing significantly to advancements in plasma physics.

Beyond his professional achievements, Dennis cherished his role as a husband, father, grandfather, and uncle. He is survived by his beloved wife, Dr. Linda Klee-Mueller of Hopewell, NJ; his sons, Dr. Luke Mueller (Diana) of Glen Head, NY, and Colby Mueller of Pennington, NJ; and his cherished grandsons, Grant Mueller and Grady Mueller of Glen Head, NY. Dennis also leaves behind his siblings, Jamie Mueller (Diana) of Milan, IL; Sharon Myers (Chuck) of Huntsville, AL; and Mark Mueller (Dena) of Orion, IL. Dennis was very close to his in-laws, who were like family to him: Joy Laker (Larry), Karen Penwell (Bob), and Sandy Brummet (Dennis), their children, and grandchildren: Kelly, Bryan, Katy, Deanna, Sophie, Allison, Chelsey, Emily, Alaina, Grace, Daniel, and Luke.

Dennis was predeceased by his parents, Warren and Margie Mueller; his dear sister, Trysh Farber; his loving father-in-law and mother-in-law, Robert and Dolores Klee; and his precious niece, Leah Penwell.

In addition to his scientific pursuits and devotion to family life, Dennis embraced a variety of hobbies that brought him immense joy. He was an avid fly fisherman who spent countless hours fishing the West Branch of the Delaware River near Hancock, NY. His passion for fishing took him to Alaska for king and coho salmon expeditions and to Montana, Wyoming, and Idaho for trout fishing adventures. One of his greatest joys was taking his grandsons out on his boat in the hopes of passing down his love for fishing.

Dennis also had a green thumb and enjoyed gardening as well as growing orchids. A vintner at heart, he took pride in crafting wine. Soccer held a special place in Dennis's life-it was a family affair that included travels to Europe to attend World Cup games.

Dennis's legacy is one of intellectual curiosity paired with a zest for life's simple pleasures. His contributions to science will continue to inspire future generations while his memory will live on in the hearts of those who knew him best.

May his memory bring comfort to all who loved him. A Celebration of Dennis's Life will be held on Saturday, August 8, 2026, from 1:00 PM to 4:00 PM at Dennis's home. The family would like to remember him in a comfortable, informal atmosphere, just as Dennis would want it.

Please no flowers, instead, memorial contributions in Dennis's memory may be made to Doctors Without Borders: https://give.doctorswithoutborders.org/

Arrangements and cremation services were under the direction of the Holcombe-Fisher Funeral Home, 147 Main Street, Flemington, NJ 08822. For further information or to send an online condolence, please visit www.holcombefisher.com.