Orbital surveys and state resource management

The resource management implications of satellite earth resource surveys for the state of Ohio are discussed. Discussions cover environmental problems, planning future developments, and short- and long-range benefits of such resource management

Closed Geodesics on Godel-type Backgrounds

We consider radial oscillations of supertube probes in the Godel-type background which is U-dual to the compactified pp-wave obtained from the Penrose limit of the NS five-brane near horizon geometry. The supertube probe computation can be carried over directly to a string probe calculation on the U-dual background. The classical equations of motion are solved explicitly. In general, the probe is not restricted to travel unidirectionally through any global time coordinate. In particular, we find geodesics that close.Comment: latex, 15 pages, 1 figure. v3: reference added, clarifications added and some discussions expande

Direct measurements of helium and hydrogen ion concentration and total ion density to an altitude of 940 kilometers

Measurement of ion concentration and total ion density in exosphere using mass spectrometer and electrostatic prob

Ionosphere Electron Temperature Measurements and Their Implications

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147864/1/jgrtb00020.pd

Use of Langmuir probes in non-Maxwellian space plasmas

Disturbance of the Maxwellian plasma may occur in the vicinity of a spacecraft due to photoemission, interactions between the spacecraft and thermospheric gases, or electron emissions from other devices on the spacecraft. Significant non-Maxwellian plasma distributions may also occur in nature as a mixture of ionospheric and magnetospheric plasmas or secondaries produced by photoionization in the thermosphere or auroral precipitation. The general formulas for current collection (volt–ampere curves) by planar, cylindrical, and spherical Langmuir probes in isotropic and anisotropic non-Maxwellian plasmas are examined. Examples are given of how one may identify and remove the non-Maxwellian components in the Langmuir probe current to permit the ionospheric parameters to be determined. Theoretical volt–ampere curves presented for typical examples of non-Maxwellian distributions include: two-temperature plasmas and a thermal plasma with an energetic electron beam. If the nonionospheric electrons are Maxwellian at a temperature distinct from that of the ionosphere electrons, the volt–ampere curves can be fitted directly to obtain the temperatures and densities of both electron components without resorting to techniques that attempt to derive the plasma distribution from the current by taking derivatives. For an arbitrary isotropic distribution, the current for retarded particles is shown to be identical for the three geometries. For anisotropic distributions, the three probe geometries are not equally suited for measuring the ionospheric electron temperature and density or for determining the distribution function in the presence of non-Maxwellian background electrons. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70117/2/RSINAK-70-7-3015-1.pd

Reflections on the face of Japan: A multivariate craniofacial and odontometric perspective

Craniofacial variables for modern and prehistoric Japanese were subjected to multivariate analysis to test the relationships of the people of Japan with mainland Asian and Oceanic samples. The modern Japanese are tied to Koreans, Chinese, Southeast Asians, and the Yayoi rice agriculturalists who entered Japan in 300 B.C. Together they make up a Mainland-Asia cluster of related populations. The prehistoric JØmon foragers, the original inhabitants of the Japanese archipelago, are the direct ancestors of the modern Ainu, who made a recognizable contribution to the warrior class—the Samurai—of feudal Japan. Together, they are associated with Polynesians and Micronesians in a JØmon-Pacific cluster of related populations. JØmon-to-Ainu tooth size reduction proceeded at the same rate as that observable in the post-Pleistocene elsewhere in the Old World.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37647/1/1330780110_ftp.pd

Electron temperatures during rapid subauroral ion drift events

International audienceExamples of data from DE-2 satellite instruments are presented. These illustrate the behaviour of plasma parameters in the F-region and adjacent topside ionosphere during rapid sub-auroral ion drift (SAID) events. In particular, a variety of behaviours of the electron temperature (Te) is demonstrated, both within and equatorward of the SAID region. The Sheffield University plasmasphere-ionosphere model (SUPIM) is used to perform calculations in which a model SAID is applied to a plasma flux tube. The model results indicate that strongly elevated ion temperature (a recognised signature of SAID events) is on occasion sufficient to raise Te to observed values by ion-electron heat transfer. On other occasions, an additional heat source is required. It is suggested that such a source for the electron gas may be due to interaction between the ring current and the plasmasphere at high altitudes. The magnitude of the downward heat flux is consistent with that necessary to produce sub-auroral red arcs. The resulting strongly heated electron gas causes vibrational excitation of molecular nitrogen in the thermosphere

Plasma waves observed at low altitudes in the tenuous Venus nightside ionosphere

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95128/1/grl7140.pd

The magnetic state of the lower ionosphere during Pioneer Venus entry phase

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95051/1/grl7136.pd