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Matsumoto, H.

Publications and source records attributed to Matsumoto, H..

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Late Holocene Cliff Retreat in Del Mar, CA, Revealed From Shore Platform 10 Be Concentrations and Numerical Modeling

Rocky coast cliff retreat presents a hazard to coastal communities and infrastructure that is potentially amplified under rising sea level conditions, among other factors. Unfortunately, constraints on retreat rates are typically limited to those derived from imagery and maps spanning the last ~100 years. Here, we use a newly developed coupled model of shore platform profile evolution and cosmogenic radionuclide production that considers the influence of relative sea level (RSL) rise, weathering, material resistance, and wave height decay to model cliff retreat over millennial timescales and its potential drivers in Del Mar, California. We demonstrate the ability to use topographic and bathymetric measurements from a narrow shore platform along with a limited data set of nine cosmogenic 10Be concentrations extending ~125 m from the cliff base to obtain modeled cliff retreat rates that steadily range from 5.0 to 12.5 cm yr -1 over the last two millennia until 100 years before present. These rates are consistent with modern retreat rates of about 2–19 cm yr -1 here. RSL rise in Southern California remained relatively constant during the late Holocene, potentially explaining the relatively stable modeled cliff retreat rate over this time. We also explore the relative influence of weathering, material resistance, and wave erosion efficacy and find that both weathering and wave-driven erosion are necessary to replicate the measured data at this location, with the latter exerting a stronger control on model acceptance, suggesting that waves may provide a possible mechanism by which RSL rise may influence coastal cliff erosion in southern California.

58 GEOSCIENCES↗
NASA NTRS2016

Ray-Tracing Simulation and In-Orbit Performance of the ASTRO-H Hard X-Ray Telescope (HXT)

A ray-trace simulation code for the Hard X-ray Telescope (HXT) on board the Hitomi (ASTRO-H) satellite is beingdeveloped. The half power diameter and effective area simulated based on the code are consistent with groundmeasurements within 10%. The HXT observed the pulsar wind nebula G21.5-0.9 for 105 ksec. We confirmed that theencircled energy function and the half power diameter obtained from the data are consistent with the ground measurements.

Matsumoto, H.↗
NASA NTRS2012

Design and Tests of the Hard X-Ray Polarimeter X-Calibur

X-ray polarimetry promises to give qualitatively new information about high-energy astrophysical sources, such as binary black hole systems, micro-quasars, active galactic nuclei, and gamma-ray bursts. We designed, built and tested a hard X-ray polarimeter X-Calibur to be used in the focal plane of the InFOC(mu)S grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 10 - 80 keY X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity.

Beilicke, M.↗
NASA NTRS2011

Design and Tests of the Hard X-Ray Polarimeter X-Calibur

X-ray polarimetry promises to give new information about high-energy astrophysical sources, such as binary black hole systems, micro-quasars, active galactic nuclei, and gamma-ray bursts. We designed, built and tested a hard X-ray polarimeter X-Calibur to be used in the focal plane of the InFOC(mu)S grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 10-80 keV X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity.

Beilicke, M.↗
NASA NTRS2004

Source and Propagation Characteristics of Kilometric Continuum Observed with Multiple Satellites

Kilometric continuum radiation was first identified with the GEOTAIL Plasma Wave Instrument (PWI) as the high frequency extension of escaping continuum emissions in the frequency range from 100 kHz to 800 kHz. It consists of from a few to many narrow-band emissions. It was observed mainly near the magnetic equator, and its source was expected to be inside of the plasmapause and the topside equatorial region. Recently, data from the IMAGE Radio Plasma Imager (RPI) and Extreme ultraviolet (EUV) experiments have been used to show that kilometric continuum is generated at the plasmapause, in or near the magnetic equator, within a notch region, and have confirmed the expectation. Data from the CRRES PWI have also identified other sources from the equatorial density irregularities. An example of CRRES observations reveals a possibility that kilometric continuum has been radiated as a wide beam emission. The IMAGE and GEOTAIL simultaneous observations are not like the previous observations since they show it has been observed to have a very broad emission cone. It could also be the highest frequency continuum enhancement so far observed since it is associated with a high energy electron injection event.

Hashimoto, K.↗
NASA NTRS2004

Suzaku Reveals He-burning Products in the X-ray Emitting Planetary Nebula BD +30deg 3639

BD +30deg 3639, the brightest planetary nebula at X-ray energies, was observed with Suzaku, an X-ray observatory launched on 2005 July 10. Using the X-ray Imaging Spectrometer, the K-lines from C VI, O VII, and O VIII were resolved for the first time, and C/O, N/O, and Ne/O abundance ratios determined. The C/O abundance ratio exceeds the solar value by nearly two orders of magnitude, and that of Ne/O by at least a factor of 5. These results indicate that the X-rays are emitted mainly by helium shell-burning products.

Murashima, M.↗
NASA NTRS2003

Measurement of Electron Spectrum to High Energies with the BESS-1999 Experiment

We present our preliminary electron spectra (e(-)). The data were obtained with the BESS instrument during a balloon flight from Canada in 1999. Electrons constitute less than 1% of the total cosmic radiation. However, due to their small mass they suffer severe energy loss through Bremsstrahlung radiation with the interstellar gas and, synchrotron and inverse Compton processes in galactic magnetic and radiation fields, respectively. As a result, their spectral shape is modified differently than that of nuclei during propagation. Thus, by studying the electron component one can gain additional information on the cosmic ray transport in the Galaxy. The Balloon-borne Experiment with Superconducting Spectrometer (BESS) is designed as a high-resolution spectrometer with a large geometry factor to provide accurate measurements of the galactic cosmic radiation (/Z/ is less than 3).

Hams, T.↗
NASA NTRS2003

Near-source and Remote Observations of Kilometric Continuum Radiation from Multispacecraft Observations

[I] Kilometric continuum (KC) radiation was first identified from Geotail plasma wave observations. Past authors have shown that this emission has a frequency range that overlaps that of the auroral kilometric radiation (AKR) but is characterized by a fine structure of narrow-bandwidth, linear features that have nearly constant or drifting frequency. This fine structure is distinct from that of AKR. KC also apparently has a distinct source region probably associated with the low-latitude inner magnetosphere, consistent with direction-finding and ray-tracing results. We present new high-resolution electric and magnetic field observations of KC obtained by the Polar plasma wave instrument in the near-source region. These observations show intense electrostatic and less intense electromagnetic emissions near the magnetic equator at the plasmapause. Simultaneously, Geotail, located at 20 to 30 RE in radial distance, observes KC in the same frequency range. These data support a possible mode-conversion source mechanism near a region of high-density gradient. High-resolution data obtained from wideband receivers on board both Polar and Cluster show closely spaced bands of emission near the magnetic equator that may be due to many nearby independent sources of EM emission perhaps associated with density fluctuations or cavities in the plasmasphere.

Menietti, J. D.↗
NASA NTRS2002

Progress in Search for Antihelium with BESS

We have searched for antihelium nuclei in cosmic rays using the data obtained from balloon flights of the BESS magnetic spectrometer. The search was mainly based on track-quality selection, followed by rigidity analysis, and on the time-of-flight and dE/dx measurements by the scintillation counter hodoscope. We analysed all the data collected during 1993-2000 with a common analysis procedure. No antihelium nuclei events were found in the energy range from 1 to 14 GV. In order to determine a new upper limit, we have simulated the loss in the air and in the instrument of He (He-bar) using the GEANT/GHEISHA code. Combined with the data collected in 1993 through 2000, a new 95 % confidence upper limit for the ratio of He-bar/He at the top of the atmosphere of 6.8 x 10(exp -7) has been obtained to be after correcting for the interactions in the air and in the instruments.

Sasaki, M.↗
NASA NTRS2001

Expression of heat shock protein 72 in atrophied rat skeletal muscles

Changes in the expression of heat shock protein 72 (HSP72) in response to atrophic-inducing perturbations of muscle involving chronic mechanical unloading and denervation were determined. Adult male Wistar rats were assigned randomly to a sedentary cage control (CON), hind limb unloading (HU, via tail suspension), HU plus tenotomy (HU + TEN), HU plus denervation (HU + DEN), or HU + TEN + DEN group. Tenotomy and DEN involved cutting the Achilles tendon and removing a segment of the sciatic nerve, respectively. After 5 days, HSP72 levels in the soleus of the HU + DEN and HU + TEN + DEN groups were 42 (P < 0.05) and 53% (P < 0.01) less than CON, respectively. Soleus weight decreased in both groups. Heat shock protein 72 levels in the plantaris of the HU + TEN, HU + DEN, and HU + TEN + DEN groups were 31, 25, and 30% lower than CON, respectively (P < 0.05). Plantaris weight decreased in the HU + DEN and HU + TEN + DEN, but not in the HU + TEN group. Hind limb unloading alone had little effect on the HSP72 level in either muscle. Reduced levels of HSP72 were associated with a decreased soleus (r=0.62, P < 0.01) and plantaris (r=0.78, P < 0.001) weight. These results indicate that the levels of HSP72 in both a slow and a fast rat plantarflexor are responsive to a chronic decrease in the levels of loading and/or activation and suggest that the neuromuscular activity level and the presence of innervation of a muscle are important factors that induce HSP72 expression.

NASA Discipline Musculoskeletal↗
NASA NTRS1996

Average energetic ion flux variations associated with geomagnetic activity from EPIC/STICS on Geotail

The magnetotail ion flux measurements from the Geotail spacecraft are analyzed both with and without the application of selection criteria that identify the plasma regime in which an observation is obtained. The different results are compared with each other. The initial results on the changes of energetic ion flux and composition correlated to average substorm activity in different magnetotail plasma regimes are discussed. The energetic ions are measured using the energetic particles and ion composition (EPIC) experiment and the suprathermal ion composition spectrometer (STICS). The plasma, wave and field instruments of the Geotail satellite were used to identify the principle magnetotail plasma regimes of plasma sheet, lobe, and magnetospheric boundary layer, as well as the magnetosheath and solar wind. Energetic O and H ions were observed in all the plasma regimes.

Christon, S. P.↗
NASA NTRS1995

Investigation of Possible Electromagnetic Disturbances caused by Spacecraft-Plasma Interactions at 4 Radii

The proposed Small Solar Probe mission features a close approach to the sun with a perihelion of 4 radii. Carbon molecules emitted from the spacecraft's heat shield will become ionized by electron impact and photoionization. The newly created ions and electrons may generate electromagnetic and electrostatic plasma waves which are possible sources of interference with in-situ plasma measurements.

computer simulations↗
NASA NTRS1995

Latitudinal structure of a Coronal Mass Ejection inferred from Ulysses and Geotail observations

We present the first observations of a Coronal Mass Ejection (CME) by two spacecraft separated substantially in heliographic latitude. Ulysses and Geotail both see similar features in the plasma and magnetic field parameters during an interval in which Geotail is located in the deep magnetosheath (greater than 150 Earth radii) and Ulysses is located in the solar wind at 5 AU, approximately 20 S of Geotail, and approximately 51 W (in the direction of solar rotation) of Geotail. Based on the similarity in plasma and magnetic field parameters and similar inferred ejection times from the Sun for both features we argue that the same CME is observed by both spacecraft. The portion of the CME observed by Ulysses is traveling much faster than the portion observed by Geotail. Thus the CME has significant latitudinal structure since at any given time the high latitude portion of the CME extends much further out in radial distance. Furthermore, this implies that a simple calculation of the arrival time of a CME at the Earth may not be done if the observing spacecraft is located substantially away from the ecliptic plane.

Hammond, C. M.↗
NASA NTRS1994

Electrotastic Solitary Waves (ESW) in the magnetotail: BEN wave forms observed by GEOTAIL

Wave forms of BEN (Broadband Electrostatic Noise) in the geomagnetic tail were first detected by the Wave Form Capture reciever on the GEOTAIL spacecraft. The results show that most of the BEN in the plasma sheet boundary layer (PSBL) are not continuous broadband noise but are composed of a series of solitary pulses having a special form which we term 'Electrostatic Solitary Waves (ESW)'. A nonlinear BGK potential model is proposed as the generation mechanism for the ESW based upon a simple particle simulation which considers the highly nonlinear evolution of the electron beam instability. The wave forms produced by this simulation are very similar to those observed by GEOTAIL and suggest that the nonlinear dynamics of the electron beam play an essential role in the generation of ESW.

Matsumoto, H.↗
NASA NTRS1994

Detections of hard X-ray emissions from bright early-type galaxies with ASCA

Five bright elliptical galaxies in the Virgo Cluster, NGC 4365, NGC 4374 (M84), NGC 4406 (M86), NGC 4472 (M49), and NGC 4636, were observed with ASCA. In addition to the extended thermal X-ray emission of temperature kT approximately 1 keV, harder X-rays with color temperature kT greater than or equal to 2 keV were detected from all of them. The 2-10 keV luminosities of this hard component for the five galaxies, integrated within 5 min, are distributed within a relatively narrow range of (1-4) x 10(exp 40) ergs/s. The hard X-ray component is primarily attributed to the integrated emission from discrete X-ray sources. In NGC 4406 and NGC 4374 the data indicate that the hard component is contributed additionally by foreground/background emission from the hot intracluster medium (ICM) of the Virgo Cluster. The hard component of NGC 4472 seems also contributed by the Virgo ICM emission, but in this case there is evidence that the ICM brightness is locally enhanced within approximately 10 min of NGC 4472.

Matsushita, K.↗