FUSION

Stellar Fusion I : The Proton-Proton Cycle

A:	^1H + ^1H --> ^2H + e^+ + neutrino	~ 7 billion years
B:	^2H + ^1H --> ^3He + energy	~ 6 sec
C:	^3He + ^3He --> ^4He + ^1H + ^1H	~ 1/2 million years

The energy yield for this cycle is ~27 MeV.

• How many times must step A occur before step C is possible?
• Based on these reaction times, what would you guess are the two most abundant nuclei in the Sun's core?
• Which reaction rate essentially controls the lifetime of the Sun and similar stars?

Stellar Fusion II : The Carbon-Carbon Cycle

This process is another energy output process in stars older and larger than the Sun.  The energy yield is ~25MeV.

Fusion on Earth (in the lab)

A:	^2H + ^2H --> ^3He + n	3.3 MeV
B:	^2H + ^2H --> ^3H + p	4.0 MeV
C:	^2H + ^3H --> ^4He + n	17.6 MeV

Magnetic Confinement: TFTR (Princeton), JET (England)

Inertial Confinement:  National Ignition Facility, Los Alamos

Z-pinch at Sandia, Albuquerque