Mod-01 Lec-40 Fusion reactions in Stars and stellar neutrinos

So, in the previous lecture I discussed what kind of efforts are being made to create a nuclear fusion reactor in which some isotope of hydrogen will be fused to make heavier nuclei and energy will be produced. This effort is being going on for last 6 decades or so internationally, and still we have not been able to come to a situation where at least

the energy which we give to this plasma for heating at least that much should be recovered through this fusion. The best we have achieved so far it is a 60 percent of the input energy that comes as the output. Of course we are very hopeful coming decades maybe we will be able to create a nuclear fission reactor, but it has been a very difficult

task. But just in front of our eyes 8 minutes away from us we have a fantastic nuclear fusion reactor, and that is our sun where so the last 4.5 billion years hydrogen is being fused into helium and energy is being produced, and that energy is responsible for our survival all live form on the earth. So, what goes on inside the sun? How that plasma is confined

in that volume for such a long time? What kind of reactions are taking place? What are their rates and so on? So, these are the some of the questions that we will be discussing in this lecture. So, physics of the sun or physics of fusion inside the sun. So, let me show you the basic data on sun that I have put on this power point. So, go to your screens.

Now, basic data about the sun as you can see here mass is about 2 into 10 to the power 30 kilograms, in compression earth’s mass is 6 into 10 to the power 24 kilograms. Then diameter is 1.39 into 10 to the power 6 kilometer which is 109 approximately, 109 times diameter of the earth, 109 is close to 108. Suppose to be a very good number in our Indian culture.