Fusion power density demonstrated

We have long focused on power density as the central arrow of energy system evolution. The recent achievement of the Joint European Torus (JET) to set a new fusion energy record of 69.26 megajoules of heat released during a single pulse over six seconds from only 0.21 milligrams of fuel, equalling the energy released from burning 2 kilograms of coal, prompts us to update our classic figure, below and as a pdf. Thanks to long-time PHE research associate Dr. Nadedja M. Victor, now at US DOE’s National Energy Technology Laboratory.

Fuel mass per energy, including nuclear fuels. Economies of scale favor fuels suited to higher power density, thus decarbonization and finally nuclear sources, at least 10,000 times more compact than hydrocarbons.  The recent JET fusion experiment achieved density 10,000,000 times coal  with deuterium-tritium fuel.  Note: *CANDU is a pressurized heavy water reactor.  Sources of data:  https://en.wikipedia.org/wiki/Energy_density and https://euro-fusion.org/eurofusion-news/dte3record/.  Figure prepared by N.M.Victor, 2/9/2024.  Program for the Human Environment, The Rockefeller University.

Passing of Cesare Marchetti

Cesare Marchetti passed away this morning in Tuscany just short of his 96th birthday.  After meeting Cesare in 1978, Jesse Ausubel became fascinated with Cesare’s ideas about the importance and ubiquity of processes of growth and diffusion captured often in simple form by Lotka-Volterra equations and subsequently coded in our Loglet Lab software.  In the early 1980s Jesse began assisting Cesare on some projects and subsequently worked together on subjects ranging from electricity to travel to human populations and empires (see below).  And of course Leonardo Da Vinci.

Cesare is best known for Marchetti’s Constant that posits that the human time budget for travel is a little above one hour per day, since ever and everywhere, because anthropologically rooted in the dangers homo sapiens faces when outside a protected environment.

Cesare was one of the inventors of geoengineering. His most cited paper is On geoengineering and the CO2 problem (1977).

Around 1970 he was also one of the inventors of the hydrogen economy as described in this 1973 paper: Hydrogen and energy.

A bibliography with links to many of Cesare’s papers from 1952 to 2007 is here.  A second list of publications is here.

Cesare’s explorations of Leonardo are here.

Our group at The Rockefeller University always greatly enjoyed hosting Cesare in New York City, and he reciprocated with marvelous hospitality in Monteloro.

Our joint efforts included:

C Marchetti, JH Ausubel. Quantitative Dynamics of Human Empires [Color Booklet Version, 52 pages].  Adapted from Marchetti and Ausubel, International Journal of Anthropology 27(1-2):1-62, 2012. 2013

JH Ausubel, C Marchetti. Science, Conquering Child of the Church . 2003 Draft prepared for Next 1000 Years meeting, 9-10 October 2003

C Marchetti, JH Ausubel. The Next 1000 Years. 2003 Discussion paper for April 2003 Rockefeller U workshop

JH Ausubel, C Marchetti. The Evolution of Transport. The Industrial Physicist 7 (2): 20–24, 2001

JH Ausubel, C Marchetti, PS Meyer. Toward Green Mobility: The Evolution of Transport European Review 6 (2): 143–162, 1998

JH Ausubel, C Marchetti. Elektron: Electrical Systems in Retrospect and Prospect Pp. 110–134 in Technological Trajectories and the Human Environment, J.H. Ausubel and H.D. Langford, (eds.). Washington, DC: National Academy Press, 1997 Also appeared in Daedalus 125(3):139-169, Summer 1996.

C Marchetti, PS Meyer, JH Ausubel. Human Population Dynamics Revisited with the Logistic Model: How Much Can Be Modeled and Predicted? Pp. 1–30 in Technological Forecasting and Social Change vol. 53, 1996.

Requiescat in pace.