Laser produced plasma

1. LASER PRODUCED
PLASMAS
Muhammad Adeel
09050610-041

2. What is Plasma?
• Quasi neutral gas which exhibits collective behaviour.
• it is believed to comprise more than 99% of our visible
universe.
• Plasma can also be formed when an exterior source of
energy, like an electromagnetic field, is so strong that it
tears electrons free from originally neutral atoms. The
conversion of a neutral gas into a plasma can occur
extremely quickly.

3. Shielding of a Plasma by a Magnetic Field

4. Laser Produced Plasma Technology

5. Basic concepts
Typical temperature, density and expansion velocity profiles
of a plasma generated by irradiation of a solid target by a
nanosecond laser pulse focused on target at an irradiance of
10^14 W/cm2

6. • The propagation of laser light in the plasma is dominated by the presence of free electrons, and
follows the dispersion relation
• Where
• The group velocit decreases as the electron density increases
• An estimate of the temperature of laser produced plasmas can be obtained by equating
the absorbed laser intensity I absto the electron heat flux

7. • Solving for the temperature gives
that for typical parameters I abs = 10^13
W/cm^2 , f = 0.1 , ne=10^21cm^-3, gives
Te=0.6keV
• blow-off velocity is roughly equal to the
local sound speed
Typical values for the blow-off velocity range
between 10^7and 10^8 cm/sec

8. . In the general case, such a scale length is given by
where T and phi are the laser length and the focal spot diameter on the target


The Debye screening length,
the Debye sphere is very high,

9. Applications Of Laser Produced Plasmas:
• Laser-produced plasmas in medicine
• Laser-produced plasmas as unique x-ray souces for
industry and astrophysics
• Application of laser produced plasma K alpha x-ray
probe in radiation biology.