A novel intense beam-driven scheme for high yield of the tri-alpha reaction ¹¹B(p, α)2α was investigated. We used a foam target made of cellulose triacetate (TAC, C₉H₁₆O₈) doped with boron. It was then heated volumetrically by soft X-ray radiation from a laser heated hohlraum and turned into a homogenous, and long living plasma. A picosecond laser pulse was employed to generate a high-intensity energetic proton beam via the well-known Target Normal Sheath Acceleration (TNSA) mechanism. We observed up to 10¹⁰/sr α particles per laser shot. This constitutes presently the highest yield value normalized to the laser energy on target. The measured fusion yield per proton exceeds the classical expectation of beam-target reactions by up to four orders of magnitude under high proton intensities. This enhancement could be attributed to the strong electric fields and nonequilibrium thermonuclear fusion reactions as a result of the new method. Our approach shows opportunities to pursue ignition of aneutronic fusion.

laser-driven nuclear reaction, proton-boron fusion, dense plasma, alpha-particle diagnosis