Tidal dissipation in the solid cores of the major planets

If the orbital resonances in the Jovian and Saturnian satellite systems are the result of orbital evolution due to tidal dissipation then the present rates of energy dissipation ($\text{E}\text{dot}$) are >2 × 10²⁰ ergs sec^?1 (Jupiter) and ?2 × 10¹⁶ ergs sec^?1 (Saturn). These values of $\text{E}\text{dot}$ can be accounted for if the planets have rocky cores with volumes equal to those suggested by current models of the interiors and if the material of these cores is both solid and imperfectly elastic (Q_e ～ 34). The calculated values of Q_e are not strongly dependent on either the rigidity of the core or the densities of the core and the mantle. Thus, these quantities need not be known precisely. It may be significant that approximately the same value of Q_e is needed for all the major planets (Jupiter, Saturn, and Uranus) even though the values of $\text{E}\text{dot}$ for these planets differ by a factor greater than 10⁴.     

Impact fragmentation experiments of basalts and pyrophyllites

Results of impact fragmentation experiments for basalts and pyrophyllites are reported. Aluminum cylindrical projectiles were impacted on cubic basalt and pyrophyllite targets at velocities of 70 to 990 m/sec. The targets and projectiles were 20 g to 3.3 kg and 2 to 20 g in weight respectively. Weights of the fragments produced by impacts were measured and the size distributions of fragments were examined. Data of the largest fragment mass (m_L) normalized to the original target mass (M_t), m_L/M_t, correlate better with the nondimensional impact stress, P_I, a new scaling parameter introduced by H. Mizutani, Y. Takagi, and S. Kawakami (1984, in preparation) than the conventional projectile's kinetic energy per unit target mass, E/M_t, used in the previous studies. All the m_L/M_t data for basalts obtained in the present study are summarized by m_L/M_t = 2.95 × 10^?2P_I^?1 where P_I = P₀L³/YR³, P₀ = peak shock pressure, L = projectile size, R = target size and Y = material strength of target. For aluminum targets, however, the m_L/M_t is 2.5 orders of magnitude larger than that for brittle targets at impacts with the same P_I. Size distributions of fragments expressed in a log N - log (m/M_t) diagram divided into three regimes bounded by two inflection points. In each regime the curve is expressed by $\text{N (>}\text{m}\text{M}{}_{\mathrm{t}}\text{) = A (}\text{m}\text{M}{}_{\mathrm{t}}\text{)}{}^{\mathrm{?a}}$. The slopes, a, of the log $\text{N -}\text{log}\text{(}\text{m}\text{M}{}_{\mathrm{t}}\text{)}$ curves in the regimes of a large and a medium size range are positively correlated with the nondimensional impact stress, P_I, and expressed as a = C₃ + a₃log P_I. The slopes, a, in the smallest size range are, on the other hand, nearly constant and have values of $\text{0.5}\text{to}\text{0.7 (}\text{1}\text{2}\text{?}\text{2}\text{3}\text{)}$. Present results indicate that the impact fragmentation is scaled well by the new scaling parameter, P_I, of Mizutani, Takagi, and Kawakami and that the present experimental data may shed new light on planetary impact processes.     

Magnetospheric chorus: Occurrence patterns and normalized frequency

New characteristics of VLF chorus in the outer magnetosphere are reported. The study is based on more than 400 hours of broadband (0.3–12.5 kHz) data collected by the Stanford University/Stanford Research Institute VLF experiment on OGO 3 during 1966–1967. Bandlimited emissions constitute the dominant form of whistler-mode radiation in the region $\text{4? L? 10}$. Magnetospheric chorus occurs mainly from 0300 to 1500 LT, at higher L at noon than at dawn, and moves to lower L during geomagnetic disturbance, in accord with ground observations of VLF chorus. Occurrence is moderate near the equator, lower near 15°, and maximum at high latitudes (far down the field lines). The centre frequency ? of the chorus band varies as L^?3> and at low latitudes is closely related to the electron gyrofrequency on the dipole field line through the satellite. Based on the measured local gyrofrequency $\text{?}{}_{\mathrm{H}}$, the normalized frequency distribution of chorus observed within 10° of the dipole equator shows two peaks, at $\text{?}\text{?}{}_{\mathrm{H}}\text{? 0.53}$ and $\text{?}\text{?}{}_{\mathrm{H}}\text{? 0.34}$. This bimodal distribution is a persistent statistical feature of near equatorial chorus, independent of L, LT and K_p. However there is considerable variability in individual events, with chorus often observed above, below, and between these statistical peaks; in particular, it is not unusual for single emissions to cross $\text{?}\text{?}{}_{\mathrm{H}}\text{= 0.50}$. When two bands are simultaneously present individual emission elements only rarely show one-to-one correlation between bands. For low K_p the median bandwidth of the upper band, gap and lower band are all ～16% of their centre frequencies, independent of L; for higher K_p the bandwidth of the lower band increases. Bandwidth also increases with latitude beyond ~10°. Starting frequencies of narrowband emissions range throughout the band. The majority of the emissions rise in frequency at a rate between 0.2 and 2.0 kHz/sec; this rate increases with K_p and decreases with L. Falling tones are rarely observed at dipole latitudes <2.5°. The observations are interpreted in terms of whistler-mode propagation theory and a gyroresonant feedback interaction model. An exact expression is derived for the critical frequency, $\text{?}\text{?}{}_{\mathrm{H}}\text{? 0.5}$, at which the curvature of the refractive index surface vanishes at zero wave normal angle. Near this frequency rays with initial wave normal angles between 0° and ?20° are focused along the initial field line for thousands of km, enhancing the phase-bunching of incoming gyroresonant electrons. The upper peak in the bimodal normalized frequency distribution is attributed to this enhancement near the critical frequency, at latitudes of ~5°. Slightly below the critical frequency interference between modes with different ray velocities may contribute to the dip in the bimodal distribution. The lower peak may reflect a corresponding peak in the resonant electron distribution, or guiding in field-aligned density irregularities. The observations are consistent with gyroresonant generation of emissions near the equator, followed by spreading of the radiation over a range of L shells farther down the field lines.     

Empirical model of the E-region electron temperature around noon and at low magnetic activity

Electron temperature measurements made with Langmuir probes at E-region heights together with deviative absorption data show that the electrons are not in thermal equilibrium with the neutrals. Moreover, for very quiet days (A_p ? 7, K_p ? 1⁺ throughout the whole day) and hours close to noon the quotients between the electron and neutral gas temperature profiles have a similar behaviour. In this paper T_e profiles measured in situ with Langmuir probes and T_n, profiles given by neutral atmosphere models, both in the specified ionospheric conditions, are used to compute $\text{T}{}_{\mathrm{e}}\text{T}{}_{\mathrm{n}}$ profiles. Each of the profiles thus obtained is fitted by a Lorentzian curve and the variation with F_10.7 of its parameters is also fitted by simple mathematical expressions.     

Quiet-time convection electric field properties derived from keV electron measurements at the inner edge of the plasma sheet by means of GEOS-2

From an analysis of the local time distribution of the electron upper energy limit reached by the geostationary satellite GEOS-2 in cutting through the innermost part of the electron plasma sheet during fairly quiet conditions the following results have been obtained, among others. An electric field model given by $\text{E}\text{= ?▽{AR}{}^4\text{sin}\text{(φ+}\text{π}\text{4}\text{)}}$, with the dusk singular point of the forbidden region boundary at 1500, instead of at 1800 M.L.T., is in quite good agreement with the observations. This means that effects due to the shielding by the hot plasma of the inner magnetosphere from the convection electric field are quite strong in situations of low disturbance level. The quiet-time convection electric field strength at 2100 M.L.T. in the geostationary orbit obtained from this analysis varies in the range 0.15–0.3 kV/R_e. Six hours earlier or later in the satellite orbit the convection field is four times stronger. Also when the convection field varies, some information about its magnitude can be obtained from the keV electron measurements.     

On the velocity of jets powering hot spots similar to those in Cygnus A

Hot spots similar to those in the radio galaxy Cygnus A can be explained by the strong shock produced by a supersonic but classical jet \(\left( {u_{jet}< c/\sqrt 3 } \right)\) . The high integrated radio luminosity (L?2×10⁴⁴ erg s^?1) and the strength of mean magnetic field (B?2×10^?4 G) suggest the hot spots are the downstream flow of a very strong shock which generates the ultrarelativistic electrons of energy ?≥20 MeV. The fully-developed subsonic turbulence amplifies the magnetic field of the jet up to 1.6×10^?4 G by the dynamo effect. If we assume that the post-shock pressure is dominated by relativistic particles, the ratio between the magnetic energy density to the energy density in relativistic particles is found to be ?2×10^?2, showing that the generally accepted hypothesis of equipartition is not valid for hot spots. The current analysis allows the determination of physical parameters inside hot spots. It is found that:

1. The velocity of the upstream flow in the frame of reference of the shock isu ₁?0.2c. Radio observations indicate that the velocity of separation of hot spots isu _sep?0.05c, so that the velocity of the jet isu _jet=u ₁+u _sep?0.25c.
2. The density of the thermal electrons inside the hot spot isn ₂?5×10^?3 e ^? cm^?3 and the mass ejected per year to power the hot spot is ?4M ₀yr^?1.
3. The relativistic electron density is less than 20% of the thermal electron density inside the hot spot and the spectrum is a power law which continues to energies as low as 30 MeV.
4. The energy density of relativistic protons is lower than the energy density of relativistic electrons unlike the situation for cosmic rays in the Galaxy.

     

Large kinetic power in FRII radio jets

We investigate the total kinetic powers (L _j) and ages (t _age) of powerful jets of four FR II radio sources (Cygnus A, 3C 223, 3C 284, and 3C 219) by the detail comparison of the dynamical model of expanding cocoons with observed ones. It is found that these sources have quite large kinetic powers with the ratio of L _j to the Eddington luminosity (L _Edd) resides in 0.02<L _j/L _Edd<10. Reflecting the large kinetic powers, we also find that the total energy stored in the cocoon (E _c) exceed the energy derived from the minimum energy condition (E _min): 2<E _c/E _min<160. This implies that a large amount of kinetic power is carried by invisible components such as thermal leptons (electron and positron) and/or protons.     

Use of equivalency in estimating the historical size distribution of impact craters

A previous analysis of a stochastic model of lunar-type impact cratering is extended to utilize geological age data by defining a more general statistic $\text{Ω}{}_{\mathrm{i}}\text{(t)}$ to be the number of equivalent whole craters of original diameter d_i and age ≤t in an observational area A; each crater is taken to be equivalent to the fraction of its rim (or area) that is in A and not occluded by later craters. By integration of a new gain-loss differential equation, a generalization of the previous basic equation is obtained that relates the expected value $\text{ω}{}_{\mathrm{i}}\text{(t) = E[Ω}{}_{\mathrm{i}}\text{(t)]}$ to the process functions specifying the size distribution and flux of craters (primary or secondary) as they form. The results are specialized to the plausible case in which the cratered body can be subdivided into geological provinces of increasing ages t₁, t₂, …, t_i … and the size probability distribution can be approximated as constant within each of the periods t_i+1 - t_i. It is shown that use of the $\text{Ω}{}_{\mathrm{i}}$ permits, in principle, a reconstruction of the historical values of the process functions and correctly compensates for the effect of overlap by removing the false bias favoring large craters that results from the usual method of crater counting. Possible generalizations of the gain-loss equation are indicated.     

Ring current simulation in connection with interplanetary space conditions

A ring current model has been obtained which permits calculations ofD_st variations on the Earth's surface during magnetic storms. The changes in D_st are described by the equation

$\text{d}\text{d}\text{t}\text{D}{}_{\mathrm{sto}}\text{= F(EM)?}\text{D}{}_{\mathrm{sto}}\text{tau;}$

where $\text{D}{}_{\mathrm{sto}}\text{= D}{}_{\mathrm{st}}\text{-bp}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{+~tc}$; p = mnv² is solar wind pressure; F(EM) is the function, controlled by the electromagnetic parameters of interplanetary medium, of injection into ring current ; τ is the constant of ring current decay. $\text{C}\text{= C}\text{u}\text{τ?=18}\text{nT}$, where C is the level of the D_st-variation field measurements; ? is the injection function characterizing the quasisteady-state injection of energy into the ring-current region. The constant Ç is determined from the condition that the change of the ring current energy from magnetic storm commencement to end should equal the difference between the injected and dissipated energy throughout the storm. The values of the factors b and τ were found by the method of minimizing the sum of the quadratic deviations of the calculated D_st from the values observed throughout the storm : b = 0.23 nT/(eV cm^?3)^{$\text{1}\text{2}$}, τ = 8.2 h at D_st? ? 55 nT and τ = 5.8 h at -120 ? D_st ? — 55 nT. The injection function F(EM) is of the form F(EM) = d(E_y? A) at the values of the azimuthal component of the solar wind electric field E_y ? A, and F(EM) =0 at A?E_y.d = ? 1.2 × 10^?3 Ts^?1 (mV/m)^?1 and A = ? 0.9 mV m^?1 . Thus, the injection to ring current is possible at the northward B_z component of the IMF.     

A possible evolutionary track of pulsars

It is usually assumed that the dipole radiation at the spin frequency W_d is the only source of braking torque on pulsars (the POG hypothesis), but certain observations cast doubt on this. In this paper, we discuss the effect of elctromagnetic braking near the light cylinder W_em without using the POG hypothesis. We found W_em ∝ P^?3.2 (P is the pulsar period), and the total power L_t ∝ P^?3.2 (if L_t ∝ W_em). A correlation analysis between L_t and Pⁿ for a sample of 15 pulsars gives n = ?3.1, in agreement with our theoretical expectations.Our analysis based on observations shows that W_em is important or even dominant in some cases. In these cases, the evolutionary path (Fig.2) is very different from that given in /4/ where W_d is assumed to be dominant. The actual braking mechanism could be a superposition of the two (Fig.3).The gap in the $\text{P ～}\text{P}\text{?}$ diagram found by Ferguson /5/ for a sample of 80-odd pulsars persists in a larger sample of 199 pulsars. This gap, if real, implies that, for a certain range of parameter values, a neutron star is unstable, while it is stable on either side of the range.     

Numerical studies of the transport of solar protons in interplanetary space

Numerical solutions of the Fokker-Planck equation governing the transport of solar protons are obtained using the Crank-Nicholson technique with the diffusion coefficient represented by K_r=K₀r^b where r is radial distance from the Sun and b can take on positive or negative values. As b ranges from +1 to ?3, the time to the observation of peak flux decreases by a factor of 5 for 1 MeV protons when $\text{V}\text{K}{}_0\text{=}\text{3 AU}{}^{\mathrm{b?1}}$ where V is the solar wind speed. The time to peak flux is found to be very insensitive to assumptions concerning the solar and outer scattering boundary conditions and the presence of exponential time decay in the flux does not depend on the existence of an outer boundary. At $\text{V}\text{K}{}_0\text{? 15 AU}{}^{\mathrm{b?1}}$, 1 MeV particles come from the Sun by an almost entirely convective process and suffer large adiabatic deceleration at b?0 but for b=+1, large Fermi acceleration is possible at all reasonable $\text{V}\text{K}{}_0$ values. Implications of this result for the calculation and measurement of particle diffusion coefficients is discussed. At $\text{b?0}$, the pure diffusion approximation to transport overestimates by a factor 2 or more the time to peak flux but as b becomes more negative, the additional effects of convection and energy loss become less important.     

Outlying plasmasphere structure detected by whistlers

Whistlers recorded at Eights ($\text{L ? 4}$) and Byrd ($\text{f ? 7}$), Antarctica have been used to study large-scale structure in equatorial plasma density at geocentric distances $\text{?3–6}\text{R}{}_{\mathrm{E}}$. The observations were made during conditions of magnetic quieting following moderate disturbance. The structures were detected by a “scanning” process involving relative motion, at about one tenth of the Earth's angular velocity or greater, between the observed density features and the observing whistler station or stations. Three case studies are described, from 26 March 1965, 11 May 1965 and 29 August 1966. The cases support satellite results by showing outlying high density regions at $\text{?4–6}\text{R}{}_{\mathrm{E}}$ that are separated from the main plasmasphere by trough-like depressions ranging in width from $\text{?0.2}$ to 1 R_E. The structures evidently endured for periods of 12 hr or more. In the cases of deepest quieting their slow east-west motions with respect to the Earth are probably of dynamo origin. The cases observed during deep quieting (11 May 1965 and 29 August 1966) suggest the approximate rotation with the Earth of structure formed during previous moderate disturbance activity in the dusk sector. The third case, from 26 March 1965, may represent a structure formed near local midnight. The reported structures appear to be closely related to the bulge phenomenon. The present work supports other experimental and theoretical evidence that the dusk sector is one of major importance in the generation of outlying density structure. It is inferred that irregularities of the type reported here regularly develop near 4–5 R_E during moderate substorm activity. This research suggests that at least a major class of the density structures that develop near 4 R_E are tail-like in nature, joined to the main body of the plasmasphere. The apparent disagreement with Chappell's results from OGO 5, which are interpreted as showing regions of “detached” plasma beyond 5 R_E, may be related to the pronounced spatial structure of electric fields observed in high-latitude ionospheric regions that are conjugate to the magnetospheric regions in which the OGO-5 observations were made.     

The effect of a normal magnetic field component on current sheet stability

A $\text{2}\text{2}\text{5}\text{-}\text{dimensional}$ particle-mesh computer model for the simulation of the current-sheet region of the geomagnetic tail is described. Important features are (a) the use of Fast Fourier techniques for the efficient solution of Ampere's equation, (b) the incorporation of sources and sinks of particles, (c) facilities for simulating finite width effects and (d) the option of including a normal magnetic field component linking through the sheet.Simulations carried out using this model indicate that current sheets with a non-zero normal magnetic field component and an infinite width are stable. The particles trace out Speiser-like orbits in such a case. Sheets with B_normal = 0 and a finite width are unstable with respect to the ion tearing-mode instability. However the presence of a normal magnetic field stabilises the system provided ρ₀<2L_y where ρ₀ is the characteristic length associated with the normal field and where L_y is the width of the sheet.On the basis of these results it is suggested that a geomagnetic substorm occurs when the normal magnetic field drops below the critical value needed for stability.     

Damping of geomagnetic pulsations by the ionosphere

A significant sink of geomagnetic pulsation energy is due to Joule dissipation in the ionosphere. To investigate this we have computed the damping experienced by standing Alfvén waves in a dipole magnetic field. Both the uncoupled poloidal and toroidal modes are considered with Joule dissipation being introduced through a boundary condition which relates the electric and magnetic field strengths at the ionosphere, viz: $\text{4πΣ}{}_{\mathrm{p}}\text{E}\text{c}\text{= b,}\text{where}\text{Σ}{}_{\mathrm{p}}$ is the height integrated Pederson conductivity. The damping rates are strongly dependent on the ionospheric conductivity and we find that typically the normalized damping rate, $\text{γ}\text{ω}\text{,}\text{is}\text{～0.1}$ for nightside values of conductivity and ～0.01 for the dayside. This would account for the observed scale of bandwidths in pulsation signals. Away from regions of extreme damping we find γ ∝ L^?1Σ_p^?1.     

Investigation of shock waves and tangential discontinuities of the cosmic plasma by the radio interference technique

The possibility of investigation of the cosmic plasma dynamics by the radio interference technique based on a finite time of radio wave propagation between the sounding and responding stations is shown. By locating the sounding station on a spacecraft the greatest contribution to the phase difference ΔΦ(t)or the phase difference growth rate $\text{Δ?}$ between the sounding and response signals are caused by disturbances in close proximity to the spacecraft. This method permits interplanetary shock waves and tangential discontinuities to be registered and the velocities and plasma density changes on their fronts to be determined. By using experimental data of ΔΦ(t) or $\text{Δ?(t)}$ one can also obtain information about plasma concentration jump, location and motion of bow shock wave and magnetopause and plasmapause. Available experimental data about different disturbances of cosmic plasma were analysed and the requirements on frequency stability of spacecraft-borne and groundbased radio equipment were estimated to register those disturbances. In most cases relative stability 10^?11–10^?13 provided by present atomic frequency standards is sufficient.     

Changes in the ionospheric profile and the faraday factor M with Kp

Using incoherent scatter data from Millstone Hill, we investigated the variations in the shape of the daytime, mid-latitude ionospheric electron density profile associated with changes in geomagnetic activity. The analysis performed was to deduce the dependence upon the 3-hr geomagnetic index Kp of h(N_m), h(0·7 N_m) above and below N_m, the plasma scale height H_T in the range 500–1000 km, and the ratio $\text{N(1000)}\text{N(h}{}_{\mathrm{m}}\text{)}$. The electron density data used spanned the solar maximum years 1968–1971. Daytime data from the period 1000 to 1600 LT were averaged separately for summer, winter and spring-fall. It is shown that the mean value $\text{M}$ of the factor M = B cos θ sec χ used by Titheridge (1972) to relate the Faraday rotation $\text{Ω}$ from a geostationary satellite to the total electron content N_N up to 2000 km is practically the same (to within 1–2 per cent) as the $\text{M}$ value used to relate the N_T and $\text{Ω}$ values both computed up to 1000 km. Taking advantage of this identity, we have used the linear relationship obtained between the ionospheric parameters and Kp to deduce the height at which $\text{M}$ should be evaluated as a function of Kp.     

Habitable zones about main sequence stars

Calculations show that a main sequence star which is less massive than the Sun has a continuously habitable zone about it which is not only closer in than the corresponding zone about the Sun, but is also relatively narrower. Let L(t) represent the luminosity after t billion years of a main sequence star of mass M, and let r_inner and r_outer represent the boundaries of the continuously habitable zone about such a star—that is, the zone in which an Earthlike planet will undergo neither a runaway greenhouse effect in the early stages of its history nor runaway glaciation after it develops an oxidizing atmosphere. Then our computer results indicate that $\text{r}{}_{\mathrm{<mtext>outer</mtext>}}\text{r}{}_{\mathrm{<mtext>inner</mtext>}}$ is roughly proportional to $\text{[}\text{L(3.5)}\text{L(1.0)}\text{]}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$. This ratio is smaller for stars less massive than the Sun (because they evolve more slowly), and the width of the continuously habitable zone about a main sequence star is therefore a strong function of the initial stellar mass. Our calculations show that r_inner = r_outer for $\text{M～0.83M?}$ (i.e., K1 stars), and it therefore appears that there is no continuously habitable zone about most K stars, nor any about M stars.     

Generation of magnetic-field aligned currents,parallel electric fields,and inverted-V structures by plasma pressure inhomogeneities in the magnetosphere

Magnetic-field aligned currents driven by plasma pressure inhomogeneities (plasma clouds) in the distant magnetosphere are analyzed quantitatively. A parallel potential drop is found to be established in the upward current region whenever a spatial scale D₀ for the pressure gradient in the equatorial magnetosphere is smaller than $\text{≈ 3g}{}_0\text{B}{}_{\mathrm{i}}\text{B}{}_0$, where g₀ is a hot electron gyroradius in the equatorial magnetic field B₀ (B_i denotes the magnetic induction in the ionosphere). A theoretical derivation is given for the experimentally observed linear relation T = AE_p + T₀ between the characteristic energy T of precipitating magnetospheric electrons and the peak energy E_p in inverted-V electron spectra. Three-dimensional potential structures accelerating electrons earthward are shown to be established beneath some model clouds which could correspond to a large scale inverted-V structure and to a thin (~ 1 km) auroral arc.     

X-ray Radiation Mechanisms and the Beaming Effect of Hot Spots and Knots in AGN Jets

The observed broadband spectral energy distributions (SEDs) of 22 hot spots and 45 knots are modelled with single-zone lepton models. Considering the sources at rest, the X-rays of some hot spots can be explained by the SSC model with magnetic field being consistent with the equipartition magnetic field in magnitude of order 1, but at the same time an unreasonably low magnetic field is required to model the X-rays for all knots. When considering the relativistic bulk motion of the sources, the IC/CMB model well explains the X-ray emission for most of them under the equipartition condition. We show that the ratio of observational luminosity R _L is tentatively correlated with the co-moving equipartition magnetic field $B_{\rm eq}^{\prime}$ and the beaming factor ??. These facts suggest that the observational differences of the X-rays from the knots and hot spots may be mainly due to the differences in the Doppler boosting effect and the co-moving magnetic field of the two kinds of source.     

Small-scale turbulence in the atmosphere of Venus

Previous studies based on radio scintillation measurements of the atmosphere of Venus have identified two regions of small-scale temperature fluctuations located in the vicinity of 45 and 60 km. A global study of the fluctuations near 60 km, which are consistent with wind-shear-generated turbulence, was conducted using the Pioneer Venus measurements. The structure constants of refractive index fluctuations c_n² and temperature fluctuations c_T² increase poleward, peak near 70° latitude, and decrease over the pole; c_n² varies from 2 × 10^?15 to 1.5 × 10^?14m^{$\text{2}\text{3}$} and c_T² from 4 × 10^?3 to 7 × 10^?2°K²m^{$\text{?2}\text{3}$}. These results indicate greater turbulent activity at the higher latitudes. In the region near 45 km the refractive index fluctuations and the corresponding temperature fluctuations are substantially lower. Based on the analysis of one representative occultation measurement, $\text{c}{}_{\mathrm{<mtext>n</mtext>}}{}^2\text{= 2 × 10}{}^{\mathrm{?16}}\text{m}{}^{\mathrm{<mtext>?2</mtext><mtext>3</mtext>}}\text{and}\text{c}{}_{\mathrm{<mtext>T</mtext>}}{}^2\text{= 7.3 × 10}{}^{\mathrm{?4}}\text{°}\text{K}{}^2\text{m}{}^{\mathrm{<mtext>?2</mtext><mtext>3</mtext>}}$ in the 45-km region. The fluctuations in this region also appear to be consistent with wind-shear-generated turbulence. The turbulence level is considerably weaker than that at 60 km; the energy dissipation rate ε is 4.9 × 10^?5m²sec^?3 and the small-scale eddy diffusion coefficient K is 2 × 10³ cm² sec^?1.