Z. Feizulin and Y. Kravtsov, Radiophys. Quantum Electron. 10, 33 (1967).

A. Gurvich and V. Tatarski, Radio Sci. 10, 3 (1975).

A. Kon and Z. Feizulin, Radiophys. Quantum Electron. 13, 51 (1970).

Note that Eq. (4) has been obtained from Eq. (11) of Ref. 1, by using the fact that *D*_{x} + *D*_{S} = *D*_{1} and the definition *D*_{x}(ρ-ρ′, ρ_{1}-ρ_{2})=〈[χ(ρ,ρ_{1})-χ(ρ′,ρ_{2})]2〉 =2σ^{2}_{x}-2*B*_{x}(ρ-ρ′,ρ_{1}-ρ_{2}), where *B*_{x}(ρ-ρ′,ρ_{1}-ρ_{2})≡(χ(ρ,ρ_{1})χ(ρ′,ρ_{2})〉-〈χ〉^{2}.

R. Fante, J. Opt. Soc. Am. 66, 74 (1976).

For weak turbulence the proof of this statement is readily seen from Eq. (5) of Ref. 5. For strong turbulence the proof follows from a realization that measured data^{2} indicate the field statistics are nearly log normal. If we compare the Markov approximation solution for 〈*u*〉 = 〈exp[χ+ *iS*]〉 with the solution obtained by assuming χ and *S* are Gaussian variables we find that 〈χ*S*〉 = 0 is required for the two solutions to be identical. For nearly log-normal field statistics it can be shown that 〈χ*S*〉 ≪ 1.

A formal definition for ε is given by ε^{2}=(∫^{L}_{0}*s*^{2}*C*^{2}_{n}(*s*)*ds*) (∫*L*_{0}*ds**C*^{2}_{n}(*s*))-1, where *s*=*L* - *x* is the distance measured from the surface of the earth. In this paper we shall use Hufnagel's model for *C*^{2}_{n}(*s*). For a description of this model see R. Hufnagel, OSA Topical Meeting on Propagation through Turbulence, Paper WA1-1, Boulder, Colo., July 1974.

For weak turbulence the proof of this statement is readily seen from Eq. (5) of Ref. 5. For strong turbulence the proof follows from a realization that measured data^{2} indicate the field statistics are nearly log normal. If we compare the Markov approximation solution for 〈*u*〉 = 〈exp[χ+ *iS*]〉 with the solution obtained by assuming χ and *S* are Gaussian variables we find that 〈χ*S*〉 = 0 is required for the two solutions to be identical. For nearly log-normal field statistics it can be shown that 〈χ*S*〉 ≪ 1.

A formal definition for ε is given by ε^{2}=(∫^{L}_{0}*s*^{2}*C*^{2}_{n}(*s*)*ds*) (∫*L*_{0}*ds**C*^{2}_{n}(*s*))-1, where *s*=*L* - *x* is the distance measured from the surface of the earth. In this paper we shall use Hufnagel's model for *C*^{2}_{n}(*s*). For a description of this model see R. Hufnagel, OSA Topical Meeting on Propagation through Turbulence, Paper WA1-1, Boulder, Colo., July 1974.

^{8}From Eq. (19) is is quite clear that (27) is the appropriate form for all interferometer spacings such that *D*_{R} ≫ ελκ_{m} = 5. 91ελ/*l*_{0}. Assuming λ ~0.6 × 10^{-6} m, *l*_{0} ~ 10^{-3} m, and ε ~ 10^{3} m, we see that for *D*_{R} ≫3 m, ρ_{N} is the correct parameter. For *D*_{R} ≪3 m it is correct to use the form in Eq. (24). It is therefore only for relatively small values of *D*_{R} that the form used in Eq. (27) is only approximate.

D. Gezari, A. Labeyrie, and R. Stachnik, Bull. Am. Astron. Soc. 3, 244 (1971).

D. Korff, J. Opt. Soc. Am. 63, 971 (1973).

Let us consider *r*= ρ_{0}(*F/L*) | f | and see what value we get for *r* if λ*F* | f | = ρ_{p}. For visible light (λ ~ 0.6 × 10^{-6} m) and typical atmospheric turbulence (*C*^{2}_{n} ~ 10^{-15} m^{-2/3}, ε ~ 10^{3} m) we find that *r*= 6.5 cos^{11/5} η. Therefore the requirement that λ*F* | f | ≫ ρ_{0} means that *r* ≫ 6.5 cos^{11/3} η. For η = 80° we then find that *r* must be greater than 0.14. Next let us consider the restrictions placed on *r* by the condition λ*F* | f | ≫*K*^{-1}_{m}. For the aforementioned atmospheric conditions this leads to the requirement that *r*≫0.025 cos^{8/5} η.

J. Shapiro (private communication, 1975).