Page 102 - High Power Laser Handbook

72 G a s , C h e m i c a l , a n d F r e e - E l e c t r o n L a s e r s Chemical Lasers 73

where P = power
X = chlorine molar flow rate
Cl2
U = chlorine utilization
F = SOG-delivered singlet delta fraction
∆
1
N = estimated number of O ( ∆) consumed by dissociation
2
costs and deactivation per initial I molecule
2
X = iodine molar flow rate
I2
F thres = lasing threshold singlet delta fraction
η mix = loss factor associated with imperfect mixing
η = loss factor associated with imperfect optical extraction
extract
In practice, the best reported small-scale device results have exceeded
0.3 (30%) chemical efficiency, based on this definition.
As is the case for HF and DF devices, very sophisticated laser cav-
ity three-dimensional fluid mechanics computer models, including
chemistry and physical optics, have been developed to predict per-
formance. Their primary limitation appears to be uncertainties in
kinetic processes and initial conditions, rather than in their ability to
solve computational problems.

3.4.7 COIL Laser Performance
High-energy laser COIL technology has been developed primarily by
the Air Force Research Labs (AFRL), which has led to the megawatt-
class Airborne Laser (ABL). Practical engineered devices are fairly
complicated. Figure 3.24 shows the Boeing 747 airplane, which houses
the ABL, equipped with a beam director, in the nose of the airplane.
The ABL fired in flight for the first time in August 2009 and was able
to engage and destroy a ballistic missile in boost phase in February
2010, reemphasizing the potential of laser weapons.

Figure 3.24 Boeing 747 Airborne Laser (ABL) platform.