Question

37. The criteria for formation of plasma are.
(A) Debye length is much smaller than the dimension
of plasma
(B) Number of particles with in debye sphere is much
greater than unity
(C) Plasma frequency is much greater than the
collision frequency of the particle
(D) All ofthe above​

Answer 1

Answer:

1: A dc electric field field E is applied at t=0 to a plasma of electron density and

collision frequency v. How would the current density evolve with time?

Solution:

The equation of motion for electrons is

v



+ = -

E



Multiplying by -noe and writing =- noe , we obtain

+ =

Multiply both sides by exp ( ) , rewrite this equation as

=

and integrate,

= dt

= .

is zero at t=0 and rises to the steady state value on the time scale of v-1

,the collision

time

Explanation: