Physical power sources Section II Fundamentals of Fusion Enery
Section II Fundamentals of Fusion Enery Physical power sources
Fusion Enery How is such powerful energy in the sun achieved? How much energy does the sun radiate per second? 3.8×1026J How many kilos does the sun The sun lose per second? Solar central temperature:106 K(core 4×109kg temperature up to 15 million degrees) Very high pressure:300 billion atmospheres ●A lot of particles Considerable time span The reaction cross section is large enough
Fusion Enery How is such powerful energy in the sun achieved? Solar central temperature: 106 K (core temperature up to 15 million degrees) Very high pressure: 300 billion atmospheres A lot of particles Considerable time span The reaction cross section is large enough The sun How much energy does the sun radiate per second? 3.8× 1026 J How many kilos does the sun lose per second? 4×109 kg
Fusion Enery Main nuclear reactions in the sun p+p=D+(e+)+y 0.42 MeV (p质子，D氘，e+正电子，y中微子；反应寿命7*109年)； D+p=3He +r 5.5 MeV (3He氦3，r光子，反应寿命4秒) 3He+3He =4He +2p 12.86 MeV (4*105年)。 4p=4He+2(et)+2y+24.7MeV
Fusion Enery p+p=D+(e+ )+ 0.42 MeV (p质子,D氘,e+正电子, 中微子;反应寿命7*109年); D+p= 3He +r 5.5 MeV ( 3He -氦3, r光子,反应寿命4秒); 3He+ 3He = 4He +2p 12.86 MeV (4*105年)。 4p= 4He +2(e+ )+2 +24.7MeV Main nuclear reactions in the sun
Fusion Enery D+D-T(1.01 MeV)+P(3.03 MeV) D+D-He3(0.82 MeV)+n(2.45 MeV) D+T-He4(3.52 MeV)+n(14.06 MeV) 氢原子核的两个同位素 具有两个质子 的氨原子核 自由中子 108 K,300 billion atmospheres There are several main types of controllable fusion: Ultrasonic fusion Laser confinement(inertial confinement)fusion Magnetic confinement fusion
Fusion Enery D+D→T(1.01 MeV)+P(3.03 MeV) D+D→He3(0.82 MeV)+n(2.45 MeV) D+T→He4(3.52 MeV)+n(14.06 MeV) There are several main types of controllable fusion: Ultrasonic fusion Laser confinement (inertial confinement) fusion Magnetic confinement fusion 108 K, 300 billion atmospheres
Fusion Enery Two Different Ways to Fusion Lawson Criterion:nx≥3.9xl0'(s/mm),T约为l0K。 must be achieved Temperature must be around T=6...15 eV Two ways to fulfil Lawson criterion: (1)First solution (magnetically confined plasmas):increase confinement time (1014~1016/cm3,0.01~1s) (2)Other solution (inertial confinement fusion -ICF): increase density of fusion plasma(1023/cm3,ns)
Fusion Enery • Lawson Criterion: must be achieved • Temperature must be around T = 6 ... 15 eV • Two ways to fulfil Lawson criterion: (1) First solution (magnetically confined plasmas): increase confinement time (1014～1016/cm3 , 0.01～1s) (2) Other solution (inertial confinement fusion - ICF): increase density of fusion plasma (1023/cm3 , ns) Two Different Ways to Fusion 要实现受控核聚变，必须满足两个基本条件，一是必须将燃料加热到很高的热核反应 温度；二是，必须在足够时间长时间内将高温高密度等离子体约束在一起。Lawson 判据限 定了实现核聚变的具体条件，即受约束的等离子体必须达到一定的密度 n 、温度 T 及约束 时间 。对氘氚反应， 3.9 10 ( / ) 11 3 n s mm ，T 约为 K 8 10