Radial Distance

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D L Turner - One of the best experts on this subject based on the ideXlab platform.

  • Radial gradients of phase space density of the outer radiation belt electrons prior to sudden solar wind pressure enhancements
    Geophysical Research Letters, 2008
    Co-Authors: D L Turner, X Li
    Abstract:

    [1] When Earth’s magnetosphere is impacted by a sudden solar wind pressure enhancement, dayside trapped electrons are transported Radially inwards, conserving their first and second adiabatic invariants (m and K). Thus, with magnetic field and particle flux measurements at geosynchronous orbit (GEO) before and after the impact, the phase space density (PSD) Radial gradients of the particles prior to the impact can be reconstructed. We show two examples, in which the PSD of low-m electrons, which correspond to energies less than � 100 keV, increases slightly with increasing Radial Distance for one event and remains unchanged for the other, while that of high-m electrons decreases significantly with increasing Radial Distance from GEO for both events. These results suggest that the PSD Radial gradients are m dependent, and a significant heating, which violates m and K, occurs inside GEO for the high energy electrons for the two cases examined. Citation: Turner, D. L., and X. Li (2008), Radial gradients of phase space density of the outer radiation belt electrons prior to sudden solar wind pressure enhancements, Geophys. Res. Lett., 35, L18101, doi:10.1029/2008GL034866.

  • Radial gradients of phase space density of the outer radiation belt electrons prior to sudden solar wind pressure enhancements
    Geophysical Research Letters, 2008
    Co-Authors: D L Turner
    Abstract:

    [1] When Earth’s magnetosphere is impacted by a sudden solar wind pressure enhancement, dayside trapped electrons are transported Radially inwards, conserving their first and second adiabatic invariants (m and K). Thus, with magnetic field and particle flux measurements at geosynchronous orbit (GEO) before and after the impact, the phase space density (PSD) Radial gradients of the particles prior to the impact can be reconstructed. We show two examples, in which the PSD of low-m electrons, which correspond to energies less than � 100 keV, increases slightly with increasing Radial Distance for one event and remains unchanged for the other, while that of high-m electrons decreases significantly with increasing Radial Distance from GEO for both events. These results suggest that the PSD Radial gradients are m dependent, and a significant heating, which violates m and K, occurs inside GEO for the high energy electrons for the two cases examined. Citation: Turner, D. L., and X. Li (2008), Radial gradients of phase space density of the outer radiation belt electrons prior to sudden solar wind pressure enhancements, Geophys. Res. Lett., 35, L18101, doi:10.1029/2008GL034866.

Marty Grove - One of the best experts on this subject based on the ideXlab platform.

  • age trends in garnet hosted monazite inclusions from upper amphibolite facies schist in the northern grouse creek mountains utah
    Geochimica et Cosmochimica Acta, 2008
    Co-Authors: Thomas D Hoisch, Michael L Wells, Marty Grove
    Abstract:

    Abstract We performed in situ Th–Pb dating of monazite in upper amphibolite facies pelitic schist from the Grouse Creek Mountains in northwest Utah. Sixty-six ages from inclusions in four garnet grains range from 37 to 72 Ma and decrease with Radial Distance from garnet cores. The age range of 30 matrix monazite grains overlaps and extends to younger ages than inclusions (25–58 Ma). The monazite grains are not intersected by cracks in the garnets, through which dissolution, reprecipitation or Pb loss might occur, and are generally too small (

  • age trends in garnet hosted monazite inclusions from upper amphibolite facies schist in the northern grouse creek mountains utah
    Geochimica et Cosmochimica Acta, 2008
    Co-Authors: Thomas D Hoisch, Michael L Wells, Marty Grove
    Abstract:

    We performed in situ Th–Pb dating of monazite in upper amphibolite facies pelitic schist from the Grouse Creek Mountains in northwest Utah. Sixty-six ages from inclusions in four garnet grains range from 37 to 72 Ma and decrease with Radial Distance from garnet cores. The age range of 30 matrix monazite grains overlaps and extends to younger ages than inclusions (25– 58 Ma). The monazite grains are not intersected by cracks in the garnets, through which dissolution, reprecipitation or Pb loss might occur, and are generally too small (<20 lm) to allow for more than one age determination on any one grain. Processes that might explain inclusion ages that decrease with Radial Distance from garnet cores include: (1) Pb diffusion in monazite, (2) dissolution and reprecipitation of monazite, and (3) co-crystallization of monazite and garnet. After consideration of these possibilities, it is concluded that the co-crystallization of monazite and garnet is the most plausible, with monazite neoblasts deriving REEs from the breakdown of muscovite. Garnet ages derived by regression of the inclusion ages and assuming a constant rate of volume increase during garnet growth yield model ages with a maximum difference between core and rim of 22 m.y.

X Li - One of the best experts on this subject based on the ideXlab platform.

  • Radial gradients of phase space density of the outer radiation belt electrons prior to sudden solar wind pressure enhancements
    Geophysical Research Letters, 2008
    Co-Authors: D L Turner, X Li
    Abstract:

    [1] When Earth’s magnetosphere is impacted by a sudden solar wind pressure enhancement, dayside trapped electrons are transported Radially inwards, conserving their first and second adiabatic invariants (m and K). Thus, with magnetic field and particle flux measurements at geosynchronous orbit (GEO) before and after the impact, the phase space density (PSD) Radial gradients of the particles prior to the impact can be reconstructed. We show two examples, in which the PSD of low-m electrons, which correspond to energies less than � 100 keV, increases slightly with increasing Radial Distance for one event and remains unchanged for the other, while that of high-m electrons decreases significantly with increasing Radial Distance from GEO for both events. These results suggest that the PSD Radial gradients are m dependent, and a significant heating, which violates m and K, occurs inside GEO for the high energy electrons for the two cases examined. Citation: Turner, D. L., and X. Li (2008), Radial gradients of phase space density of the outer radiation belt electrons prior to sudden solar wind pressure enhancements, Geophys. Res. Lett., 35, L18101, doi:10.1029/2008GL034866.

Thomas D Hoisch - One of the best experts on this subject based on the ideXlab platform.

  • age trends in garnet hosted monazite inclusions from upper amphibolite facies schist in the northern grouse creek mountains utah
    Geochimica et Cosmochimica Acta, 2008
    Co-Authors: Thomas D Hoisch, Michael L Wells, Marty Grove
    Abstract:

    Abstract We performed in situ Th–Pb dating of monazite in upper amphibolite facies pelitic schist from the Grouse Creek Mountains in northwest Utah. Sixty-six ages from inclusions in four garnet grains range from 37 to 72 Ma and decrease with Radial Distance from garnet cores. The age range of 30 matrix monazite grains overlaps and extends to younger ages than inclusions (25–58 Ma). The monazite grains are not intersected by cracks in the garnets, through which dissolution, reprecipitation or Pb loss might occur, and are generally too small (

  • age trends in garnet hosted monazite inclusions from upper amphibolite facies schist in the northern grouse creek mountains utah
    Geochimica et Cosmochimica Acta, 2008
    Co-Authors: Thomas D Hoisch, Michael L Wells, Marty Grove
    Abstract:

    We performed in situ Th–Pb dating of monazite in upper amphibolite facies pelitic schist from the Grouse Creek Mountains in northwest Utah. Sixty-six ages from inclusions in four garnet grains range from 37 to 72 Ma and decrease with Radial Distance from garnet cores. The age range of 30 matrix monazite grains overlaps and extends to younger ages than inclusions (25– 58 Ma). The monazite grains are not intersected by cracks in the garnets, through which dissolution, reprecipitation or Pb loss might occur, and are generally too small (<20 lm) to allow for more than one age determination on any one grain. Processes that might explain inclusion ages that decrease with Radial Distance from garnet cores include: (1) Pb diffusion in monazite, (2) dissolution and reprecipitation of monazite, and (3) co-crystallization of monazite and garnet. After consideration of these possibilities, it is concluded that the co-crystallization of monazite and garnet is the most plausible, with monazite neoblasts deriving REEs from the breakdown of muscovite. Garnet ages derived by regression of the inclusion ages and assuming a constant rate of volume increase during garnet growth yield model ages with a maximum difference between core and rim of 22 m.y.

Michael L Wells - One of the best experts on this subject based on the ideXlab platform.

  • age trends in garnet hosted monazite inclusions from upper amphibolite facies schist in the northern grouse creek mountains utah
    Geochimica et Cosmochimica Acta, 2008
    Co-Authors: Thomas D Hoisch, Michael L Wells, Marty Grove
    Abstract:

    Abstract We performed in situ Th–Pb dating of monazite in upper amphibolite facies pelitic schist from the Grouse Creek Mountains in northwest Utah. Sixty-six ages from inclusions in four garnet grains range from 37 to 72 Ma and decrease with Radial Distance from garnet cores. The age range of 30 matrix monazite grains overlaps and extends to younger ages than inclusions (25–58 Ma). The monazite grains are not intersected by cracks in the garnets, through which dissolution, reprecipitation or Pb loss might occur, and are generally too small (

  • age trends in garnet hosted monazite inclusions from upper amphibolite facies schist in the northern grouse creek mountains utah
    Geochimica et Cosmochimica Acta, 2008
    Co-Authors: Thomas D Hoisch, Michael L Wells, Marty Grove
    Abstract:

    We performed in situ Th–Pb dating of monazite in upper amphibolite facies pelitic schist from the Grouse Creek Mountains in northwest Utah. Sixty-six ages from inclusions in four garnet grains range from 37 to 72 Ma and decrease with Radial Distance from garnet cores. The age range of 30 matrix monazite grains overlaps and extends to younger ages than inclusions (25– 58 Ma). The monazite grains are not intersected by cracks in the garnets, through which dissolution, reprecipitation or Pb loss might occur, and are generally too small (<20 lm) to allow for more than one age determination on any one grain. Processes that might explain inclusion ages that decrease with Radial Distance from garnet cores include: (1) Pb diffusion in monazite, (2) dissolution and reprecipitation of monazite, and (3) co-crystallization of monazite and garnet. After consideration of these possibilities, it is concluded that the co-crystallization of monazite and garnet is the most plausible, with monazite neoblasts deriving REEs from the breakdown of muscovite. Garnet ages derived by regression of the inclusion ages and assuming a constant rate of volume increase during garnet growth yield model ages with a maximum difference between core and rim of 22 m.y.