297 results on '"Harada, Y."'
Search Results
2. Locally Generated ULF Waves in the Martian Magnetosphere: MAVEN Observations
- Author
-
Harada, Y., Ruhunusiri, S., Halekas, J. S., Espley, J., DiBraccio, G. A., Mcfadden, J. P., Mitchell, D. L., Mazelle, C., Collinson, G., Brain, D. A., Hara, T., Nosé, M., Oimatsu, S., Yamamoto, K., and Jakosky, B. M.
- Abstract
We investigate Martian ultralow frequency (ULF) electromagnetic waves generated by local plasma instabilities below the Martian bow shock. Recent Mars Atmosphere and Volatile EvolutioN (MAVEN) observations have shown that ULF waves generated upstream of the Martian bow shock can propagate down to the upper ionosphere, possibly facilitating heavy ion escape from Mars by heating the ionospheric plasma. In contrast to the upstream waves oscillating near the upstreamproton cyclotron frequency, we identify narrow band ULF magnetic field fluctuations with frequencies near the localproton cyclotron frequency (fcp(local)) from MAVEN data. In addition to expected proton cyclotron waves locally generated in the magnetosheath, we newly identify compressional narrow band emissions near fcp(local)(and its harmonics for some cases) in the dayside upper ionosphere and in the nightside magnetotail. The dayside waves are preferentially observed for high solar extreme ultraviolet (EUV) conditions and are often associated with ring/shell‐like, hot protons of magnetosheath origin in the presence of cold, dense ionospheric protons. The nightside waves exhibit distinct preference for high‐solar‐EUV, strong‐solar‐wind conditions, under which both warm and cold protons are enhanced. The observed properties of these compressional waves are generally consistent with a proton Bernstein mode instability driven by a positive perpendicular slope in proton velocity distribution functions. The excited waves can cause perpendicular heating of thermal protons, thereby transferring energy from precipitating hot protons to cold ionospheric protons. MAVEN observes narrow band ULF waves near the local proton cyclotron frequency below the Martian bow shockCompressional narrow band emissions are newly identified in the dayside upper ionosphere and in the nightside magnetotailThe wave‐particle interaction facilitates energy transfer from hot protons of magnetosheath origin to cold ionospheric protons
- Published
- 2019
- Full Text
- View/download PDF
3. Spacecraft Outgassing Observed by the BepiColombo Ion Spectrometers
- Author
-
Fränz, M., Rojo, M., Cornet, T., Hadid, L. Z., Saito, Y., André, N., Varsani, A., Schmid, D., Krüger, H., Krupp, N., Delcourt, D., Katra, B., Harada, Y., Yokota, S., Verdeil, C., Aizawa, S., Millilo, A., Orsini, S., Mangano, V., Fiethe, B., Benkhoff, J., and Murakami, G.
- Abstract
During the first flyby of the BepiColombo composite spacecraft at Mercury in October 2021 ion spectrometers observed two intense spectral lines with energies between 10 and 70 eV. The spectral lines persisted also at larger distances from Mercury and were observed again at lower intensity during cruise phase in March 2022 and at the second and third Mercury flyby as a single band. The ion composition indicates that water is the dominant gas source. The outgassing causes the composite spacecraft to charge up to a negative potential of up to −50 V. The distribution and intensity of the lower energy signal depends on the intensity of low energy electron fluxes around the spacecraft which again depend on the magnetic field orientation. We interpret the observation as being caused by water outgassing from different source locations on the spacecraft being ionized in two different regions of the surrounding potential. The interpretation is confirmed by two dimensional particle‐in‐cell simulations. The BepiColombo spacecraft is on its way through the inner solar system in a composite configuration consisting of two satellites and a propulsion unit with two large solar arrays. This configuration will only be separated after orbit insertion in December 2025. During the cruise phase and planetary flybys in the years 2021–2023 the ion spectrometers onboard the two satellites observed strong fluxes of low energy positive ions. We interpret these observations as being caused by outgassing of water from the spacecraft and a negative charging of the spacecraft caused by a high electron density surrounding the spacecraft. Around the first Mercury flyby in October 2021 all ion spectrometers observed two separate peaks in the low energy ion spectra. We explain these as being caused by water molecules being ionized by strong photon and electron fluxes in different regions of the negative potential surrounding the spacecraft. From these different potential regions ions are accelerated back to the spacecraft. Strong outgassing from the BepiColombo spacecraft was observed during first Mercury Flyby in 2021 and later during interplanetary cruiseThe gas composition is dominated by water moleculesThe ion energy spectra sometimes show a double band structure which we interpret as being caused by different ionization locations within a negative spacecraft potential Strong outgassing from the BepiColombo spacecraft was observed during first Mercury Flyby in 2021 and later during interplanetary cruise The gas composition is dominated by water molecules The ion energy spectra sometimes show a double band structure which we interpret as being caused by different ionization locations within a negative spacecraft potential
- Published
- 2024
- Full Text
- View/download PDF
4. Ultrathin and lightweight lobster eye optics formed into a single flat substrate
- Author
-
Khounsary, Ali M., Goto, Shunji, Morawe, Christian, Doi, K., Nomoto, K., Nawaki, Y., Uetsuki, K., Hata, R., Tsuruoka, K., Kodaka, H., Ito, H., Harada, Y., and Asakawa, Y.
- Published
- 2019
- Full Text
- View/download PDF
5. Forming an ultrathin and lightweight x-ray micropore optics into a single substrate
- Author
-
Khounsary, Ali M., Goto, Shunji, Morawe, Christian, Nomoto, K., Doi, K., Nawaki, Y., Uetsuki, K., Hata, R., Tsuruoka, K., Kodaka, H., Itoh, H., Harada, Y., and Asakawa, Y.
- Published
- 2019
- Full Text
- View/download PDF
6. Does Magnetic Reconnection Occur in the Near Lunar Surface Environment?
- Author
-
Sawyer, R. P., Halekas, J. S., Bonnell, J. W., Chen, L. J., McFadden, J., Glassmeier, K. H., Harada, Y., and Stanier, A.
- Abstract
The near lunar surface contains small‐scale magnetic field structures that provide a natural test bed for observing plasmas with a non‐zero Hall electric field, as well as potentially facilitating electron‐only reconnection. This study presents observational evidence of magnetized electrons as well as demagnetized ions when THEMIS‐ARTEMIS probe B reached an altitude of ∼15 km above the lunar surface. Additionally, observations suggest the presence of a field line topology change and traversal of a closed magnetic field structure containing solar wind electrons, suggestive of magnetic reconnection having occurred at some point between the solar wind interplanetary magnetic field and a lunar crustal magnetic field. Thus, the observations presented here are consistent with previous studies that predict prominent Hall electric fields near lunar crustal magnetic fields and further suggest that the solar wind interplanetary magnetic field may reconnect with lunar crustal magnetic fields, most likely via electron‐only reconnection. While interactions between the solar wind and the Earth's magnetosphere have been well studied, there is still much to be learned by studying the interactions between the solar wind and the small‐scale lunar magnetic fields. Due to the small‐scale nature of the lunar magnetic fields, previous studies have suggested that the ions do not respond in the same manner as the electrons. The resulting effects lead to an electric field near regions of lunar magnetic fields. This study presents observational evidence of the aforementioned phenomena. Additionally, the spacecraft observations also suggest that magnetic reconnection, or the breaking of the lunar magnetic field lines and reconnection to the magnetic field in the solar wind, was occurring between the solar wind and the lunar magnetic fields. Observations suggest magnetic reconnection occurs between the solar wind IMF and lunar crustal magnetic fieldsElectron pitch angle and velocity distributions suggest the spacecraft traversed a closed magnetic topology containing solar wind electronsWe report in‐situ observations of demagnetized ions and associated Hall electric fields near the lunar surface Observations suggest magnetic reconnection occurs between the solar wind IMF and lunar crustal magnetic fields Electron pitch angle and velocity distributions suggest the spacecraft traversed a closed magnetic topology containing solar wind electrons We report in‐situ observations of demagnetized ions and associated Hall electric fields near the lunar surface
- Published
- 2023
- Full Text
- View/download PDF
7. A Tenuous Lunar Ionosphere in the Geomagnetic Tail
- Author
-
Halekas, J. S., Poppe, A. R., Harada, Y., Bonnell, J. W., Ergun, R. E., and McFadden, J. P.
- Abstract
We utilize measurements of electron plasma frequency oscillations made by the two‐probe Acceleration, Reconnection, Turbulence, and Electrodynamics of Moon's Interaction with the Sun mission to investigate the charged particle density in the lunar environment as the Moon passes through the Earth's geomagnetic tail. We find that the Moon possesses a tenuous ionosphere with an average density of ~0.1–0.3 cm−3, present at least 50% of the time in the geomagnetic tail, primarily confined to within a few thousand kilometers of the dayside of the Moon. The day‐night asymmetry and dawn‐dusk symmetry of the observed plasma suggests that photoionization of a neutral exosphere with dawn‐dusk symmetry produces the majority of the lunar‐derived plasma. The lunar plasma density commonly exceeds the ambient plasma density in the tail, allowing the presence of the lunar ionosphere to appreciably perturb the local plasma environment. Though usually considered an airless body, the Moon actually possesses a very tenuous atmosphere. Ionization of this atmosphere, primarily by sunlight, creates a lunar ionosphere roughly one million times more tenuous than that of the Earth. At most times, this ionosphere does not noticeably affect the surrounding environment. However, when the Moon passes through the near vacuum of the geomagnetic tail of the Earth each lunar month around full Moon, its presence becomes more important. In this unique environment, the lunar‐derived charged particle density becomes comparable to the ambient value, and the presence of the lunar ionosphere can appreciably affect its surroundings. We utilize measurements from lunar orbit to investigate the density, structure, and dynamics of the faint lunar ionosphere and its interaction with the local environment of the geomagnetic tail. When the Moon passes through the geomagnetic tail, a tenuous ionosphere exists at least 50% of the time above the dayside lunar surfaceThe day‐night asymmetry and dawn‐dusk symmetry of the observed ionosphere favors formation by photoionization of a symmetric exosphereThe lunar‐derived plasma density commonly exceeds the ambient density in the tail, allowing lunar plasma to locally perturb the environment
- Published
- 2018
- Full Text
- View/download PDF
8. MARSIS Observations of the Martian Nightside Ionosphere During the September 2017 Solar Event
- Author
-
Harada, Y., Gurnett, D. A., Kopf, A. J., Halekas, J. S., Ruhunusiri, S., DiBraccio, G. A., Espley, J., and Brain, D. A.
- Abstract
We present topside ionospheric sounding on the nightside of Mars during the September 2017 solar event by Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on board Mars Express along with complementary dayside observations from Mars Atmosphere and Volatile EvolutioN (MAVEN). The MARSIS and MAVEN observations during the event suggest that (i) the nightside bottomside ionosphere was significantly enhanced by solar energetic particles, (ii) the nightside peak electron density was increased to unusually high values of ∼1–2 ×104cm−3around 120 km altitudes owing to enhanced electron impact ionization, and (iii) the ionospheric magnetic field was globally amplified by the high dynamic pressure during the interplanetary coronal mass ejection passage. These multipoint measurements help elucidate the global response of the Martian upper ionosphere to the solar event. The solar flare that occurred on 10 September 2017, and the subsequent coronal mass ejection had major impacts on the upper atmosphere of Mars. In this work, we study how the Martian ionosphere, which is the ionized part of the upper atmosphere, changed in response to this prominent solar event. Analysis of data from two spacecraft, Mars Express and MAVEN, reveals unusually strong magnetic fields everywhere in the ionosphere and an exceptionally high level of ionization during the night time. These results can be compared and combined with other observations and models and help the ongoing community wide effort to understand the effects of the solar event on planetary environments. MARSIS on the nightside and MAVEN on the dayside observed the global response of the Martian ionosphere to the September 2017 solar eventNightside peak electron densities and global ionospheric magnetic fields exhibited unusually high values during the eventElectron impact ionization is a likely source for the nightside peak electron density enhancement around 120 km altitudes
- Published
- 2018
- Full Text
- View/download PDF
9. Magnetic Reconnection on Dayside Crustal Magnetic Fields at Mars: MAVEN Observations
- Author
-
Harada, Y., Halekas, J. S., DiBraccio, G. A., Xu, S., Espley, J., Mcfadden, J. P., Mitchell, D. L., Mazelle, C., Brain, D. A., Hara, T., Ma, Y. J., Ruhunusiri, S., and Jakosky, B. M.
- Abstract
The identification of magnetic reconnection on the dayside of Mars has been elusive owing to the lack of comprehensive plasma and field measurements. Here we present direct measurements of dayside in situ reconnection signatures by the comprehensive particles and fields package on board the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft over strong crustal magnetic fields in the southern hemisphere of Mars. During a crossing of a bifurcated current sheet consisting of northward and southward magnetic fields, MAVEN recorded (i) ionospheric photoelectrons trapped on closed magnetic field lines, (ii) Hall magnetic fields and a nonzero normal field with polarity consistent with a crossing northward of the X line, and (iii) northward Alfvénic ion jets. Dayside magnetic reconnection on crustal magnetic fields could control the global configuration and topology of the Martian magnetosphere and alter the ion escape pattern from the dayside ionosphere. Magnetic reconnection is a fundamental and universal process in space plasmas. The occurrence of magnetic reconnection on the dayside of Mars has been long speculated but never been definitively demonstrated by comprehensive evidence of “smoking gun.” This paper presents Mars Atmosphere and Volatile EvolutioN observations of ions, electrons, and magnetic fields that collectively demonstrate that magnetic reconnection can operate above strong crustal magnetic fields on the dayside of Mars. This process could explain the “twisted” tail of Mars recently discovered by Mars Atmosphere and Volatile EvolutioN and may play an important role in modifying the atmospheric escape from Mars. MAVEN provides the first comprehensive evidence for in situ magnetic reconnection signatures over crustal magnetic fields on the dayside of MarsObserved signatures include closed magnetic topology, Hall and normal magnetic fields, and ion jets within a bifurcated current sheetDayside reconnection could control the global magnetospheric configuration and dayside ion escape pathways
- Published
- 2018
- Full Text
- View/download PDF
10. One‐Hertz Waves at Mars: MAVEN Observations
- Author
-
Ruhunusiri, Suranga, Halekas, J. S., Espley, J. R., Eparvier, F., Brain, D., Mazelle, C., Harada, Y., DiBraccio, G. A., Thiemann, E. M. B., Larson, D. E., Mitchell, D. L., Jakosky, B. M., and Sulaiman, A. H.
- Abstract
We perform a survey of 1‐Hz waves at Mars utilizing Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft observations for a Martian year. We find that the 1‐Hz wave occurrence rate shows an apparent variation caused by masking of the waves by background turbulence during the times when the background turbulence levels are high. To correct for this turbulence masking, we select waves that occur in time intervals where the background turbulence levels are low. We find that the extreme ultraviolet flux does not affect the wave occurrence rate significantly, suggesting that the newly born pickup ions originating in the Mars's exosphere contribute minimally to the 1‐Hz wave generation. We find that the wave occurrence rates are higher for low Mach numbers and low beta values than for high Mach numbers and high beta values. Further, we find that a high percentage of 1‐Hz waves satisfy the group‐standing condition, which suggests that a high percentage of the waves seen as monochromatic waves in the spacecraft frame can be broadband waves in the solar wind frame that have group velocities nearly equal and opposite to the solar wind velocity. We infer that the wave occurrence rate trends with the Mach number and proton beta are a consequence of how the Mach numbers and beta values influence the wave generation and damping or how those parameters affect the group‐standing condition. Finally, we find that the 1‐Hz waves are equally likely to be found in both the quasi‐parallel and the quasi‐perpendicular foreshock regions. One‐hertz waves at Mars show an apparent occurrence rate variation due to masking of the waves during times of high background turbulence levelsThe wave occurrence rates vary significantly with Mach numbers and proton beta values but do not vary significantly with EUV flux levelsThe 1‐Hz waves are observed in both the quasi‐parallel and quasi‐perpendicular foreshock regions with comparable occurrence rates
- Published
- 2018
- Full Text
- View/download PDF
11. MAVEN Observations of Solar Wind‐Driven Magnetosonic Waves Heating the Martian Dayside Ionosphere
- Author
-
Fowler, C. M., Andersson, L., Ergun, R. E., Harada, Y., Hara, T., Collinson, G., Peterson, W. K., Espley, J., Halekas, J., Mcfadden, J., Mitchell, D. L., Mazelle, C., Benna, M., and Jakosky, B. M.
- Abstract
We present Mars Atmosphere and Volatile EvolutioN observations of large‐amplitude magnetosonic waves propagating through the magnetosheath into the Martian ionosphere near the subsolar point on the dayside of the planet. The observed waves grow in amplitude as predicted for a wave propagating into a denser, charged medium, with wave amplitudes reaching 25 nT, equivalent to ∼40% of the background field strength. These waves drive significant density and temperature variations (∼20% to 100% in amplitude) in the suprathermal electrons and light ion species (H+) that correlate with compressional fronts of the magnetosonic waves. Density and temperature variations are also observed for the ionospheric electrons, and heavy ion species (O+and O 2+); however, these variations are not in phase with the magnetic field variations. Whistler waves are observed at compressional wave fronts and are thought to be produced by unstable, anistropic suprathermal electrons. The magnetosonic waves drive significant ion and electron heating down to just above the exobase region. Ion heating rates are estimated to be between 0.03 and 0.2 eVs−1per ion, and heavier ions could thus gain escape energy if located in this heating region for ∼10–70 s. The measured ionospheric density profile indicates severe ionospheric erosion above the exobase region, and this is likely caused by substantial ion outflow that is driven by the observed heating. The effectiveness of these magnetosonic waves to energize the plasma close to the exobase could have important implications for the long‐term climate evolution for unmagnetized bodies that are exposed to the solar wind. Magnetosonic waves are observed to propagate from the magnetosheath into the dayside Martian ionosphereMagnetosonic waves are observed to drive large variations in ionospheric density and temperatureWave energy is absorbed by the dense O 2+ionosphere, leading to significant ion heating and substantial ionospheric erosion
- Published
- 2018
- Full Text
- View/download PDF
12. High expression of ABCG2 induced by EZH2 disruption has pivotal roles in MDS pathogenesis
- Author
-
Kawabata, K C, Hayashi, Y, Inoue, D, Meguro, H, Sakurai, H, Fukuyama, T, Tanaka, Y, Asada, S, Fukushima, T, Nagase, R, Takeda, R, Harada, Y, Kitaura, J, Goyama, S, Harada, H, Aburatani, H, and Kitamura, T
- Abstract
Both proto-oncogenic and tumor-suppressive functions have been reported for enhancer of zeste homolog 2 (EZH2). To investigate the effects of its inactivation, a mutant EZH2 lacking its catalytic domain was prepared (EZH2-dSET). In a mouse bone marrow transplant model, EZH2-dSET expression in bone marrow cells induced a myelodysplastic syndrome (MDS)-like disease in transplanted mice. Analysis of these mice identified Abcg2 as a direct target of EZH2. Intriguingly, Abcg2 expression alone induced the same disease in the transplanted mice, where stemness genes were enriched. Interestingly, ABCG2 expression is specifically high in MDS patients. The present results indicate that ABCG2 de-repression induced by EZH2 mutations have crucial roles in MDS pathogenesis.
- Published
- 2018
- Full Text
- View/download PDF
13. Ionospheric Irregularities at Mars Probed by MARSIS Topside Sounding
- Author
-
Harada, Y., Gurnett, D. A., Kopf, A. J., Halekas, J. S., and Ruhunusiri, S.
- Abstract
The upper ionosphere of Mars contains a variety of perturbations driven by solar wind forcing from above and upward propagating atmospheric waves from below. Here we explore the global distribution and variability of ionospheric irregularities around the exobase at Mars by analyzing topside sounding data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express. As irregular structure gives rise to off‐vertical echoes with excess propagation time, the diffuseness of ionospheric echo traces can be used as a diagnostic tool for perturbed reflection surfaces. The observed properties of diffuse echoes above unmagnetized regions suggest that ionospheric irregularities with horizontal wavelengths of tens to hundreds of kilometers are particularly enhanced in the winter hemisphere and at high solar zenith angles. Given the known inverse dependence of neutral gravity wave amplitudes on the background atmospheric temperature, the ionospheric irregularities probed by MARSIS are most likely associated with plasma perturbations driven by atmospheric gravity waves. Though extreme events with unusually diffuse echoes are more frequently observed for high solar wind dynamic pressures during some time intervals, the vast majority of the diffuse echo events are unaffected by varying solar wind conditions, implying limited influence of solar wind forcing on the generation of ionospheric irregularities. Combination of remote and in situ measurements of ionospheric irregularities would offer the opportunity for a better understanding of the ionospheric dynamics at Mars. MARSIS observes diffuse ionospheric echoes, which are indicative of ionospheric irregularities around the exobase at MarsThe winter hemisphere and high solar zenith angles are strongly favored for observations of the diffuse echoesThe ionospheric irregularities are driven primarily by atmospheric gravity waves and secondarily by solar wind forcing
- Published
- 2018
- Full Text
- View/download PDF
14. 541 Gene set enrichment analysis identifies biological networks associated with skin aging in a large Japanese population: Data from the Nagahama cohort
- Author
-
Latreille, J., Thorn, G., Jdid, R., Gendronneau, G., Tabara, Y., Harada, Y., Forestier, S., Chelala, C., and Matsuda, F.
- Published
- 2023
- Full Text
- View/download PDF
15. Dynamic response of the Martian ionosphere to an interplanetary shock: Mars Express and MAVEN observations
- Author
-
Harada, Y., Gurnett, D. A., Kopf, A. J., Halekas, J. S., Ruhunusiri, S., Lee, C. O., Hara, T., Espley, J., DiBraccio, G. A., Mitchell, D. L., Mazelle, C., Larson, D. E., and Jakosky, B. M.
- Abstract
Multipoint observations from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express and the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission reveal a dynamic response of the Martian ionosphere to abrupt variations in the upstream solar wind plasma. On 2 February 2017, MAVEN, located upstream from the Martian bow shock, encountered a corotating interaction region‐related interplanetary shock with a sudden enhancement in the dynamic pressure. MARSIS, operating in the upper ionosphere at ∼478 km altitudes and ∼78° solar zenith angles, observed a sharp increase in the local magnetic field magnitude ∼1 min after the shock passage at MAVEN. The time lag is roughly consistent with the expected propagation time of a pressure pulse from the bow shock to the upper ionosphere at the fast magnetosonic speed. Subsequently, remote soundings recorded disturbed signatures of the topside ionosphere below Mars Express. Simultaneous MEX and MAVEN observations demonstrate that the Martian ionosphere responds quickly to an interplanetary shock passageThe response time is consistent with propagation of a pressure pulse from the bow shock to the ionosphere in the fast magnetosonic modeRemote soundings reveal the presence of irregular structures in the topside ionosphere shortly after the shock passage
- Published
- 2017
- Full Text
- View/download PDF
16. Photoemission and electrostatic potentials on the dayside lunar surface in the terrestrial magnetotail lobes
- Author
-
Harada, Y., Poppe, A. R., Halekas, J. S., Chamberlin, P. C., and McFadden, J. P.
- Abstract
Despite the need to accurately predict and assess the lunar electrostatic environment in all ambient conditions that the Moon encounters, photoemission and electrostatic potentials on the dayside lunar surface in the terrestrial magnetotail lobes remain poorly characterized. We study characteristics and variabilities of lunar photoelectron energy spectra by utilizing Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) and Apollo measurements in combination with the Flare Irradiance Spectral Model (FISM). We confirm that the photoelectron spectral shapes are consistent between ARTEMIS and Apollo and that the photoelectron flux is linearly correlated with the FISM solar photon flux. We develop an observation‐based model of lunar photoelectron energy distributions, thereby deriving the current balance surface potential. The model predicts that dayside lunar surface potentials in the tail lobes (typically tens of volts) could increase by a factor of 2–3 during strong solar flares. First direct confirmation of correlation between lunar surface photoelectron flux and solar photon fluxDevelops an observation‐based model of emitted photoelectron energy spectra from lunar soilDayside lunar surface potentials in the Earth's tail lobes could increase by a factor of 2–3 during strong solar flares
- Published
- 2017
- Full Text
- View/download PDF
17. Survey of magnetic reconnection signatures in the Martian magnetotail with MAVEN
- Author
-
Harada, Y., Halekas, J. S., McFadden, J. P., Espley, J., DiBraccio, G. A., Mitchell, D. L., Mazelle, C., Brain, D. A., Andersson, L., Ma, Y. J., Larson, D. E., Xu, S., Hara, T., Ruhunusiri, S., Livi, R., and Jakosky, B. M.
- Abstract
We conduct an extended survey of reconnection signatures observed in the Martian magnetotail by the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. Although it is well established that magnetic reconnection plays a fundamental role in the dynamics of intrinsicmagnetospheres, the role of reconnection in the dynamics of inducedmagnetospheres remains poorly understood. Based on comprehensive plasma and field measurements by MAVEN in the Martian magnetotail, we first identified 776 current sheet crossings and then selected 34 crossings with Hall magnetic field signatures, which are indicative of the ion diffusion region of tail reconnection. For the majority of the identified Hall field events, we observe ion flow enhancements in the directions consistent with the reconnection outflow directions expected from the Hall magnetic field polarity. The reconnection signatures are preferentially observed in the −Ehemisphere of the near‐Mars magnetotail at ∼1–2 Mars radii downstream from Mars. We have found no strong correlation of the likelihood of observing reconnection signatures with local crustal field strengths or with upstream drivers. The duty cycle of tail reconnection is estimated to be ∼1–10% or even higher. The MAVEN observations suggest that magnetic reconnection can play an important role in the dynamics of the Martian magnetotail. First extended survey of comprehensive in situ reconnection signatures in the Martian magnetotailReconnection occurs preferentially in the −Ehemisphere of the near‐Mars magnetotailReconnection could operate for at least 1‐10% of the time in the Martian magnetotail
- Published
- 2017
- Full Text
- View/download PDF
18. Waves in the innermost open boundary layer formed by dayside magnetopause reconnection
- Author
-
Uchino, H., Kurita, S., Harada, Y., Machida, S., and Angelopoulos, V.
- Abstract
We present two Time History of Events and Macroscale Interactions during Substorms observations of whistler mode and electrostatic wave events in the innermost open boundary layer (IOBL), formed by dayside magnetopause reconnection. The IOBL is identified by high‐speed electrons from the magnetosheath on the magnetospheric side of the ion outflow from the reconnection site. Quasi‐parallel whistler mode waves propagating toward the reconnection region are observed, along with a partial shortage of magnetospheric electrons moving away from the reconnection region. Calculation of wave linear growth rates shows that the waves can be excited by the perpendicular electron temperature anisotropy that develops due to the partial shortage of field‐aligned magnetospheric electrons. Electrostatic waves close to the lower hybrid resonance frequency are observed in the IOBL in the second event, which occurred during the main phase of a magnetospheric storm. Magnetospheric electrons are almost completely lost in the event, except at pitch angles close to 90°, yet whistler mode waves are not observed. An electron beam from the magnetosheath and counterstreaming cold electrons originating from the plasmaspheric plume are observed in association with the electrostatic waves. Growth rate calculations show that the waves are likely to be ion acoustic waves excited via couplings between the flowing cold electrons and background cold ions. We suggest that differences in solar wind conditions and magnetic reconnection characteristics may control the shapes of the electron velocity distribution functions and the resulting plasma wave properties in the IOBL. Plasma waves are observed in the innermost open boundary layer formed by dayside magnetopause reconnectionWhistler mode waves are excited by electron temperature anisotropy due to the partial shortage of magnetospheric electronsIon acoustic waves may grow via instabilities between plasmaspheric electrons flowing toward the reconnection site and background cold ions
- Published
- 2017
- Full Text
- View/download PDF
19. Characterization of turbulence in the Mars plasma environment with MAVEN observations
- Author
-
Ruhunusiri, Suranga, Halekas, J. S., Espley, J. R., Mazelle, C., Brain, D., Harada, Y., DiBraccio, G. A., Livi, R., Larson, D. E., Mitchell, D. L., Jakosky, B. M., and Howes, G. G.
- Abstract
We characterize turbulence in the Mars plasma environment in a global scale for the first time by computing spectral indices for magnetic field fluctuations (slopes in the magnetic field power spectra) and determining how they vary with frequency and in different regions. In the magnetosheath, unlike in the solar wind, we find an absence of the inertial range which has a spectral index value equal to the Kolmogorov scaling value of −5/3. Instead, as observed in the magnetosheaths of other planets, we find that the spectral indices transition from low negative values close to −0.5 at low frequencies (< proton gyrofrequency) to values much lower than −5/3 at high frequencies (> proton gyrofrequency). This indicates that the pristine solar wind is modified at the Martian bow shock and that the fluctuations are dominated by locally generated fluctuations in the magnetosheath. The absence of spectral indices with the Kolmogorov scaling value indicates that the fluctuations in the magnetosheath do not have sufficient time to interact with one another leading to a fully developed energy cascade. Spectral index values near the Kolmogorov scaling value are observed for the low‐frequency range near the magnetic pileup boundary, and this indicates the presence of fully developed energy cascade. In the wake, we find that the spectral indices have approximately the same values, typically near −2, for both the low‐ and high‐frequency ranges. We observe seasonal variations of the spectral indices, mainly in the upstream region, which indicate the seasonal variations of the proton cyclotron waves. First global characterization of turbulence in the Mars plasma environmentFully developed energy cascade is absent in the magnetosheath but present in the magnetic pileup boundaryTurbulence characteristics at Mars vary seasonally
- Published
- 2017
- Full Text
- View/download PDF
20. Structure, dynamics, and seasonal variability of the Mars‐solar wind interaction: MAVEN Solar Wind Ion Analyzer in‐flight performance and science results
- Author
-
Halekas, J. S., Ruhunusiri, S., Harada, Y., Collinson, G., Mitchell, D. L., Mazelle, C., McFadden, J. P., Connerney, J. E. P., Espley, J. R., Eparvier, F., Luhmann, J. G., and Jakosky, B. M.
- Abstract
We report on the in‐flight performance of the Solar Wind Ion Analyzer (SWIA) and observations of the Mars‐solar wind interaction made during the Mars Atmosphere and Volatile EvolutioN (MAVEN) prime mission and a portion of its extended mission, covering 0.85 Martian years. We describe the data products returned by SWIA and discuss the proper handling of measurements made with different mechanical attenuator states and telemetry modes, and the effects of penetrating and scattered backgrounds, limited phase space coverage, and multi‐ion populations on SWIA observations. SWIA directly measures solar wind protons and alpha particles upstream from Mars. SWIA also provides proxy measurements of solar wind and neutral densities based on products of charge exchange between the solar wind and the hydrogen corona. Together, upstream and proxy observations provide a complete record of the solar wind experienced by Mars, enabling organization of the structure, dynamics, and ion escape from the magnetosphere. We observe an interaction that varies with season and solar wind conditions. Solar wind dynamic pressure, Mach number, and extreme ultraviolet flux all affect the bow shock location. We confirm the occurrence of order‐of‐magnitude seasonal variations of the hydrogen corona. We find that solar wind Alfvén waves, which provide an additional energy input to Mars, vary over the mission. At most times, only weak mass loading occurs upstream from the bow shock. However, during periods with near‐radial interplanetary magnetic fields, structures consistent with Short Large Amplitude Magnetic Structures and their wakes form upstream, dramatically reconfiguring the Martian bow shock and magnetosphere. SWIA provides direct and proxy measurements of solar wind input to MarsThe Mars‐solar wind interaction varies with solar wind conditions and seasonMars only perturbs the upstream medium weakly, except during radial IMF
- Published
- 2017
- Full Text
- View/download PDF
21. Effects of interface roughness on the local valence electronic structure at the SiO2/Si interface: Soft X-ray absorption and emission study
- Author
-
Yamashita, Y., Yamamoto, S., Mukai, K., Yoshinobu, J., Harada, Y., Tokushima, T., Takata, Y., Shin, S., Yamashita, Y., Yamamoto, S., Mukai, K., Yoshinobu, J., Harada, Y., Tokushima, T., Takata, Y., and Shin, S.
- Abstract
We investigated effects of interface roughness on the local valence electronic structures at SiO2/Si interface in order to clarify the relation between interface structures and interface electronic properties, by using soft X-ray absorption and emission spectroscopy. For atomically smooth interface, the local valence structures depend on intermediate oxidation states at the interface. For atomically rough interface, on the other hand, the local valence structures at the interface show amorphous-like electronic states irrespective of the intermediated oxidation states.
- Published
- 2006
- Full Text
- View/download PDF
22. MAVEN observations of electron‐induced whistler mode waves in the Martian magnetosphere
- Author
-
Harada, Y., Andersson, L., Fowler, C. M., Mitchell, D. L., Halekas, J. S., Mazelle, C., Espley, J., DiBraccio, G. A., McFadden, J. P., Brain, D. A., Xu, S., Ruhunusiri, S., Larson, D. E., Lillis, R. J., Hara, T., Livi, R., and Jakosky, B. M.
- Abstract
We report on narrowband electromagnetic waves at frequencies between the local electron cyclotron and lower hybrid frequencies observed by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft in the Martian induced magnetosphere. The peaked electric field wave spectra below the electron cyclotron frequency were first observed by Phobos‐2 in the Martian magnetosphere, but the lack of magnetic field wave data prevented definitive identification of the wave mode and their generation mechanisms remain unclear. Analysis of electric and magnetic field wave spectra obtained by MAVEN demonstrates that the observed narrowband waves have properties consistent with the whistler mode. Linear growth rates computed from the measured electron velocity distributions suggest that these whistler mode waves can be generated by cyclotron resonance with anisotropic electrons. Large electron anisotropy in the Martian magnetosphere is caused by absorption of parallel electrons by the collisional atmosphere. The narrowband whistler mode waves and anisotropic electrons are observed on both open and closed field lines and have similar spatial distributions in MSO and planetary coordinates. Some of the waves on closed field lines exhibit complex frequency‐time structures such as discrete elements of rising tones and two bands above and below half the electron cyclotron frequency. These MAVEN observations indicate that whistler mode waves driven by anisotropic electrons, which are commonly observed in intrinsic magnetospheres and at unmagnetized airless bodies, are also present at Mars. The wave‐induced electron precipitation into the Martian atmosphere should be evaluated in future studies. MAVEN observes narrowband whistler mode waves in the Martian magnetosphereThe whistler mode waves are generated by cyclotron resonance with anisotropic electronsThe whistler mode waves could play a role in electron precipitation into the Martian atmosphere
- Published
- 2016
- Full Text
- View/download PDF
23. MAVEN observations of partially developed Kelvin‐Helmholtz vortices at Mars
- Author
-
Ruhunusiri, Suranga, Halekas, J. S., McFadden, J. P., Connerney, J. E. P., Espley, J. R., Harada, Y., Livi, R., Seki, K., Mazelle, C., Brain, D., Hara, T., DiBraccio, G. A., Larson, D. E., Mitchell, D. L., Jakosky, B. M., and Hasegawa, H.
- Abstract
We present preliminary results and interpretations for Mars Atmospheric and Volatile EvolutioN (MAVEN) observations of magnetosheath‐ionospheric boundary oscillations at Mars. Using centrifugal force arguments, we first predict that a signature of fully rolled up Kelvin‐Helmholtz vortices at Mars is sheath ions that have a bulk motion toward the Sun. The sheath ions adjacent to a vortex should also accelerate to speeds higher than the mean sheath velocity. We also predict that while the ionospheric ions that are in the vortex accelerate antisunward, they never attain speeds exceeding that of the sheath ions, in stark contrast to KH vortices that arise at the Earth's magnetopause. We observe accelerated sheath and ionospheric ions, but we do not observe sheath ions that have a bulk motion toward the Sun. Thus, we interpret these observations as KH vortices that have not fully rolled up. Magnetosheath‐ionospheric boundary oscillations observed by MAVEN are interpreted as non–fully developed Kelvin‐Helmholtz vorticesSheath ions moving in the sunward direction is a signature of a fully developed KH vortex at MarsThe low spatial growth rate and the small system size of Mars preclude the KH vortices from becoming fully rolled up close to Mars
- Published
- 2016
- Full Text
- View/download PDF
24. Plasma clouds and snowplows: Bulk plasma escape from Mars observed by MAVEN
- Author
-
Halekas, J. S., Brain, D. A., Ruhunusiri, S., McFadden, J. P., Mitchell, D. L., Mazelle, C., Connerney, J. E. P., Harada, Y., Hara, T., Espley, J. R., DiBraccio, G.A., and Jakosky, B. M.
- Abstract
We present initial Mars Atmosphere and Volatile EvolutioN (MAVEN) observations and preliminary interpretation of bulk plasma loss from Mars. MAVEN particle and field measurements show that planetary heavy ions derived from the Martian atmosphere can escape in the form of discrete coherent structures or “clouds.” The ions in these clouds are unmagnetized or weakly magnetized, have velocities well above the escape speed, and lie directly downstream from magnetic field amplifications, suggesting a “snowplow” effect. This postulated escape process, similar to that successfully used to explain the dynamics of active gas releases in the solar wind and terrestrial magnetosheath, relies on momentum transfer from the shocked solar wind protons to the planetary heavy ions, with the electrons and magnetic field acting as intermediaries. Fluxes of planetary ions on the order of 107?cm-2?s-1can escape by this process, and if it operates regularly, it could contribute 10–20% of the current ion escape from Mars. Ionospheric plasma can escape from Mars in coherent structures or cloudsMomentum is transferred from the solar wind to heavy ions by magnetic fieldsA snowplow effect accelerates parcels of unmagnetized Martian plasma
- Published
- 2016
- Full Text
- View/download PDF
25. MAVEN observations of energy‐time dispersed electron signatures in Martian crustal magnetic fields
- Author
-
Harada, Y., Mitchell, D. L., Halekas, J. S., McFadden, J. P., Mazelle, C., Connerney, J. E. P., Espley, J., Brain, D. A., Larson, D. E., Lillis, R. J., Hara, T., Livi, R., DiBraccio, G. A., Ruhunusiri, S., and Jakosky, B. M.
- Abstract
Energy‐time dispersed electron signatures are observed by the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission in the vicinity of strong Martian crustal magnetic fields. Analysis of pitch angle distributions indicates that these dispersed electrons are typically trapped on closed field lines formed above strong crustal magnetic sources. Most of the dispersed electron signatures are characterized by peak energies decreasing with time rather than increasing peak energies. These properties can be explained by impulsive and local injection of hot electrons into closed field lines and subsequent dispersion by magnetic drift of the trapped electrons. In addition, the dispersed flux enhancements are often bursty and sometimes exhibit clear periodicity, suggesting that the injection and trapping processes are intrinsically time dependent and dynamic. These MAVEN observations demonstrate that common physical processes can operate in both global intrinsic magnetospheres and local crustal magnetic fields. MAVEN observes energy‐time dispersed electron signatures near Martian crustal magnetic fieldsElectrons injected into closed field lines are subsequently dispersed by magnetic driftBursty, sometimes periodic, dispersion signatures suggest dynamic injection processes
- Published
- 2016
- Full Text
- View/download PDF
26. MAVEN observations of solar wind hydrogen deposition in the atmosphere of Mars
- Author
-
Halekas, J. S., Lillis, R. J., Mitchell, D. L., Cravens, T. E., Mazelle, C., Connerney, J. E. P., Espley, J. R., Mahaffy, P. R., Benna, M., Jakosky, B. M., Luhmann, J. G., McFadden, J. P., Larson, D. E., Harada, Y., and Ruhunusiri, S.
- Abstract
Mars Atmosphere and Volatile EvolutioN mission (MAVEN) observes a tenuous but ubiquitous flux of protons with the same energy as the solar wind in the Martian atmosphere. During high flux intervals, we observe a corresponding negative hydrogen population. The correlation between penetrating and solar wind fluxes, the constant energy, and the lack of a corresponding charged population at intermediate altitudes implicate products of hydrogen energetic neutral atoms from charge exchange between the upstream solar wind and the exosphere. These atoms, previously observed in neutral form, penetrate the magnetosphere unaffected by electromagnetic fields (retaining the solar wind velocity), and some fraction reconvert to charged form through collisions with the atmosphere. MAVEN characterizes the energy and angular distributions of both penetrating and backscattered particles, potentially providing information about the solar wind, the hydrogen corona, and collisional interactions in the atmosphere. The accretion of solar wind hydrogen may provide an important source term to the Martian atmosphere over the planet's history. We observe H+and H−in the atmosphere of Mars, at the solar wind energySolar wind protons charge exchange and penetrate as ENAs then reconvertMAVEN can monitor hydrogen deposition and backscatter in the atmosphere
- Published
- 2015
- Full Text
- View/download PDF
27. Time‐dispersed ion signatures observed in the Martian magnetosphere by MAVEN
- Author
-
Halekas, J. S., McFadden, J. P., Connerney, J. E. P., Espley, J. R., Brain, D. A., Mitchell, D. L., Larson, D. E., Harada, Y., Hara, T., Ruhunusiri, S., and Jakosky, B. M.
- Abstract
Mars Atmosphere and Volatile EvolutioN mission's (MAVEN) high‐cadence measurements reveal the frequent occurrence of ion energy dispersion events inside the Martian magnetosphere. The systematics of observed dispersion signatures suggest time dispersion of a broad source spectrum over a flight distance of a few thousand kilometers and disfavor mechanisms involving spatial dispersion. Pickup of heavy planetary ions in strong variable electric fields provides one potential mechanism that could produce the observed time dispersion signatures. The periodicity of many observed dispersion signatures, with frequencies near the upstream proton cyclotron frequency, suggests a possible role for low‐frequency plasma waves in accelerating the observed ions from a source near the induced magnetospheric boundary to the observation location inside the magnetospheric tail lobes. The observed dispersion signatures may provide a new way to track the flow of energy from the upstream region through the magnetosphere and the role of waves in driving the escape of ions from the atmosphere. MAVEN regularly observes energy‐dispersed ions in the Martian magnetosphereObserved signatures are consistent with time dispersion, and often periodicThe dispersion signatures can be produced by ion pickup in variable fields
- Published
- 2015
- Full Text
- View/download PDF
28. Magnetic reconnection in the near‐Mars magnetotail: MAVEN observations
- Author
-
Harada, Y., Halekas, J. S., McFadden, J. P., Mitchell, D. L., Mazelle, C., Connerney, J. E. P., Espley, J., Larson, D. E., Brain, D. A., Andersson, L., DiBraccio, G. A., Collinson, G. A., Livi, R., Hara, T., Ruhunusiri, S., and Jakosky, B. M.
- Abstract
We report Mars Atmosphere and Volatile EvolutioN (MAVEN) observations of electrons, ions, and magnetic fields which provide comprehensive demonstration of magnetic reconnection signatures in the Martian magnetotail. In the near‐Mars tail current sheet at XMSO∼−1.3RM, trapped electrons with two‐sided loss cones were observed, indicating the closed magnetic field topology. In the closed field region, MAVEN observed Hall magnetic field signatures and Marsward bulk flows of H+, O+, and O2+ions, which suggest the presence of X lines tailward from the spacecraft. Velocity distribution functions of the reconnection outflow ions exhibit counterstreaming beams separated along the current sheet normal, and their bulk velocities in the outflow direction inversely depend on ion mass. These characteristics are in qualitative agreement with previous multispecies kinetic simulations. The near‐Mars magnetotail provides a unique environment for studying multi‐ion reconnection. We present comprehensive MAVEN observations of magnetic reconnection at MarsThe observed signatures are consistent with previous multispecies PIC simulationsMars provides a unique environment for investigation of multi‐ion reconnection
- Published
- 2015
- Full Text
- View/download PDF
29. Marsward and tailward ions in the near‐Mars magnetotail: MAVEN observations
- Author
-
Harada, Y., Halekas, J. S., McFadden, J. P., Mitchell, D. L., Mazelle, C., Connerney, J. E. P., Espley, J., Larson, D. E., Brain, D. A., DiBraccio, G. A., Curry, S. M., Hara, T., Livi, R., Ruhunusiri, S., and Jakosky, B. M.
- Abstract
We present Mars Atmosphere and Volatile EvolutioN (MAVEN) observations of Marsward and tailward fluxes of suprathermal (>25 eV) ions in the near‐Mars (∼1–1.5 Mars radii downstream) magnetotail. Statistical results show that the Marsward proton flux and magnetic field draping pattern are well organized by the upstream motional electric field direction. We observe both significant Marsward proton fluxes and tightly wrapped magnetic field lines in the hemisphere pointed in the opposite direction to the upstream electric field. These characteristics are very similar to those observed at Venus. On the other hand, the net flux of oxygen ions points tailward on average in the Martian tail, while net Venusward flows of oxygen ions were observed frequently in the same hemisphere at Venus. The mechanism by which the Marsward proton flux is produced in the presence of tailward oxygen ion flux remains unclear. Ions and magnetic fields in the near‐Mars tail are organized by the upstream electric fieldMarsward protons and wrapped field lines are observed in the −EhemisphereUnlike at Venus, net flux directions differ between protons and oxygen ions at Mars
- Published
- 2015
- Full Text
- View/download PDF
30. Strong plume fluxes at Mars observed by MAVEN: An important planetary ion escape channel
- Author
-
Dong, Y., Fang, X., Brain, D. A., McFadden, J. P., Halekas, J. S., Connerney, J. E., Curry, S. M., Harada, Y., Luhmann, J. G., and Jakosky, B. M.
- Abstract
We present observations by the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission of a substantial plume‐like distribution of escaping ions from the Martian atmosphere, organized by the upstream solar wind convection electric field. From a case study of MAVEN particle‐and‐field data during one spacecraft orbit, we identified three escaping planetary ion populations: plume fluxes mainly along the upstream electric field over the north pole region of the Mars‐Sun‐Electric field (MSE) coordinate system, antisunward ion fluxes in the tail region, and much weaker upstream pickup ion fluxes. A statistical study of O+fluxes using 3 month MAVEN data shows that the plume is a constant structure with strong fluxes widely distributed in the MSE northern hemisphere, which constitutes an important planetary ion escape channel. The escape rate through the plume is estimated to be ~30% of the tailward escape and ~23% of the total escape for > 25 eV O+ions. Three escaping planetary ion populations near Mars are identified in MAVEN observationsMAVEN observed a substantial plume with strong escaping ion fluxes over the MSE north pole regionThe plume contributes ~23% to the total >25 eV O+ escape of ~2 × 1024s−1
- Published
- 2015
- Full Text
- View/download PDF
31. The spatial distribution of planetary ion fluxes near Mars observed by MAVEN
- Author
-
Brain, D. A., McFadden, J. P., Halekas, J. S., Connerney, J. E. P., Bougher, S. W., Curry, S., Dong, C. F., Dong, Y., Eparvier, F., Fang, X., Fortier, K., Hara, T., Harada, Y., Jakosky, B. M., Lillis, R. J., Livi, R., Luhmann, J. G., Ma, Y., Modolo, R., and Seki, K.
- Abstract
We present the results of an initial effort to statistically map the fluxes of planetary ions on a closed surface around Mars. Choosing a spherical shell ~1000 km above the planet, we map both outgoing and incoming ion fluxes (with energies >25 eV) over a 4 month period. The results show net escape of planetary ions behind Mars and strong fluxes of escaping ions from the northern hemisphere with respect to the solar wind convection electric field. Planetary ions also travel toward the planet, and return fluxes are particularly strong in the southern electric field hemisphere. We obtain a lower bound estimate for planetary ion escape of ~3 × 1024s−1, accounting for the ~10% of ions that return toward the planet and assuming that the ~70% of the surface covered so far is representative of the regions not yet visited by Mars Atmosphere and Volatile EvolutioN (MAVEN). MAVEN ion measurements are mapped to a spherical surface around MarsPlanetary ion fluxes are organized in four spatial regions on the shellHeavy ion escape rates exceed 2 × 1024s−1for energies >25 eV
- Published
- 2015
- Full Text
- View/download PDF
32. Response of Mars O+pickup ions to the 8 March 2015 ICME: Inferences from MAVEN data‐based models
- Author
-
Curry, S. M., Luhmann, J. G., Ma, Y. J., Dong, C. F., Brain, D., Leblanc, F., Modolo, R., Dong, Y., McFadden, J., Halekas, J., Connerney, J., Espley, J., Hara, T., Harada, Y., Lee, C., Fang, X., and Jakosky, B.
- Abstract
We simulate and compare three phases of the Mars‐solar wind interaction with the 8 March interplanetary coronal mass ejection (ICME) event using Mars Atmosphere and Volatile EvolutioN (MAVEN) mission observations in order to derive heavy ion precipitation and escape rates. The MAVEN observations provide the initial conditions for three steady state MHD model cases, which reproduce the observed features in the solar wind density, velocity, and magnetic field seen along the MAVEN orbit. Applying the MHD results to a kinetic test particle model, we simulate global precipitation and escape maps of O+during the (1) pre‐ICME phase, (2) sheath phase, and (3) ejecta phase. We find that the Case 1 had the lowest precipitation and escape rates of 9.5 × 1025and 4.1 × 1025s−1, Case 2 had the highest rates of 9.5 × 1025and 4.1 × 1025s−1, and Case 3 had rates of 3.2 × 1025and 1.3 × 1025s−1, respectively. Additionally, Case 2 produced a high‐energy escaping plume >10 keV, which mirrored corresponding STATIC observations. The shock phase of an ICME drives the most ion escape at MarsThe shock phase of an ICME has an O+escape rate of 4.1e25/sO sputtering from the shock phase of an ICME may be on the order of 1e26/s
- Published
- 2015
- Full Text
- View/download PDF
33. A Comprehensive Model for Pickup Ion Formation at the Moon
- Author
-
Poppe, A. R., Halekas, J. S., and Harada, Y.
- Abstract
The lunar exosphere is an ensemble of multiple overlapping, noninteracting neutral distributions that reflect the primary physical processes acting on the lunar surface. While previous observations have detected and constrained the behavior of some species, many others have only circumstantial evidence or theoretical modeling suggesting their presence. Many species are so tenuous as to be unobservable by direct neutral sampling, yet in comparison, measurements in their ionized form provide a particularly sensitive method of detection. To better aid the interpretation of past measurements and planning of future observations, we present a model for the production of lunar pickup ions from the Moon consisting of two components: An analytic model for the distributions of 18 neutral species produced by various mechanisms and an analytic model for the ionization and subsequent acceleration of 20 exospheric and surface‐sputtered pickup ion species. The dominant lunar pickup ions in the model are H2+${\mathrm{H}}_{2}^{+}$, He+, CO+, 40Ar+, Al+, Na+, K+, Si+, Ca+, and O+with an asymmetric distribution favoring the positive interplanetary electric field hemisphere of the Moon. We compare the model predictions to statistically averaged pickup ion fluxes around the Moon as observed by the ARTEMIS spacecraft over the past decade. By filtering for interplanetary electric field‐aligned, high‐energy observations, we find that the pickup ion model lacks an additional source of heavy species. We suggest that a dense CO2exosphere of 3 × 104− 1 × 105cm−3could account for the missing pickup ion flux as part of the recycling of solar wind carbon ions incident to the Moon. The Moon is surrounded by a thin neutral atmosphere comprised of multiple atomic and molecular species. This atmosphere, technically termed an “exosphere,” is produced by multiple processes that are either internal or external to the Moon. As exospheric atoms and molecules are exposed to space, they are continuously ionized by photons, protons, and electrons from the Sun. Once ionized, these particles are accelerated by electromagnetic fields in interplanetary space and often lost from the Moon's environment. These “pickup ions” (so called because they are “picked up” into and carried along with the flow of particles in space by electromagnetic fields) provide information about the composition and distribution of the neutral lunar exosphere. We have constructed a model of 18 neutral and 20 ionized species in the lunar exosphere based on previous observations and/or models. The model predicts that the dominant pickup ion species in the lunar exosphere include carbon monoxide (CO+), 40‐argon (40Ar+), aluminum (Al+), sodium (Na+), and potassium (K+). The model is compared to observations of lunar pickup ions by NASA's ARTEMIS mission. We find that the model is missing a component of the pickup ion flux and suggest that the Moon may harbor a dense carbon dioxide (CO2) exosphere. We constructed an observationally based model of 18 neutral and 20 ionized species from the lunar exosphereDominant pickup ion species are H2+${\mathrm{H}}_{2}^{+}$, He+, CO+, 40Ar+, Al+, Na+, K+, Si+, Ca+, and O+with asymmetric spatial distributionThe model underestimates pickup ion fluxes when compared to ARTEMIS observations, and we suggest CO2+${\mathrm{C}\mathrm{O}}_{2}^{+}$as the missing component We constructed an observationally based model of 18 neutral and 20 ionized species from the lunar exosphere Dominant pickup ion species are H2+${\mathrm{H}}_{2}^{+}$, He+, CO+, 40Ar+, Al+, Na+, K+, Si+, Ca+, and O+with asymmetric spatial distribution The model underestimates pickup ion fluxes when compared to ARTEMIS observations, and we suggest CO2+${\mathrm{C}\mathrm{O}}_{2}^{+}$as the missing component
- Published
- 2022
- Full Text
- View/download PDF
34. Martian Ionospheric Magnetic Fluctuations Below 200 km
- Author
-
Esman, T. M., Espley, J., Gruesbeck, J., Fowler, C. M., Xu, S., Elrod, M., Harada, Y., and Giacalone, J.
- Abstract
We conduct a search for 5–16 Hz magnetic waves below 200 km and within the Martian ionosphere using data from multiple instruments onboard the Mars Atmosphere and Volatile EvolutioN mission spacecraft. We present a case study and an analysis of the 54 identified events to establish trends. Nearly half the wave events occur near the cusps of strong crustal magnetic fields (CMFs). The stronger regions have fewer events and may be a result of stronger CMFs preventing draped field lines from reaching lower altitudes. A majority of the observed magnetic waves occur on the nightside, are associated with greater fluxes of electrons traveling downward along the local magnetic field compared to those traveling upward, and correspond to increases in thermal plasma density. These aspects indicate electron precipitation was present during these wave events. We conclude that the waves are observed under magnetic field conditions favorable for the penetration of electrons and waves into the lower ionosphere, but that the electron precipitation cannot solely account for the waves or plasma changes. Martian ionospheric magnetic waves with frequencies up to 16 Hz are identified at altitudes lower than 200 km for the first timeThe waves are primarily associated with nightside plasma density increases and have electrons traveling downward along the magnetic fieldWe conclude that the waves are associated with field lines that allow wave penetration and electron precipitation at lower altitudes Martian ionospheric magnetic waves with frequencies up to 16 Hz are identified at altitudes lower than 200 km for the first time The waves are primarily associated with nightside plasma density increases and have electrons traveling downward along the magnetic field We conclude that the waves are associated with field lines that allow wave penetration and electron precipitation at lower altitudes
- Published
- 2022
- Full Text
- View/download PDF
35. Spectral Properties of Whistler‐Mode Waves in the Vicinity of the Moon: A Statistical Study With ARTEMIS
- Author
-
Sawaguchi, W., Harada, Y., Kurita, S., and Nakamura, S.
- Abstract
We present statistical analyses of whistler‐mode waves observed by Acceleration, Reconnection, and Turbulence and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS). Although some observations showed that the lunar whistler‐mode waves have similarities to the terrestrial chorus emissions, it remains unknown whether the banded structure typically seen in chorus is common to the lunar waves. In this study, we automatically detected whistler‐mode waves from 9 years of ARTEMIS data and classified them into four types of spectral shapes: lower band only, upper band only, banded, and no‐gap. We first show that a magnetic connection to the lunar surface is a dominant factor in the wave generation. The occurrence rate of whistler‐mode waves is 10 times larger on the magnetic field line connected to the Moon. Then we compared the field line connected events according to the position of the Moon and the condition of the field‐line foot point (day/night and existence of magnetic anomalies). The results show that (a) almost no banded event is observed in any circumstances, suggesting that generation mechanisms for the two band structure of the terrestrial chorus are largely ineffective around the Moon and (b) the wave occurrence rate depends on the foot point conditions, presumably affected by electrostatic/magnetic reflections deforming the velocity distribution of the resonant electrons. Thus, our results provide implications for the two band structure formation and new insights into fundamental processes of the Moon‐plasma interaction. We present a statistical study on Moon‐related whistler‐mode waves classified into four types of spectral shapes using Acceleration, Reconnection, and Turbulence and Electrodynamics of the Moon's Interaction with the Sun dataBanded waves are extremely rare, suggesting that two‐band structure formation is ineffective around the MoonWhistler‐mode wave spectra are highly variable resulting from spatial and temporal variability of the lunar plasma environment We present a statistical study on Moon‐related whistler‐mode waves classified into four types of spectral shapes using Acceleration, Reconnection, and Turbulence and Electrodynamics of the Moon's Interaction with the Sun data Banded waves are extremely rare, suggesting that two‐band structure formation is ineffective around the Moon Whistler‐mode wave spectra are highly variable resulting from spatial and temporal variability of the lunar plasma environment
- Published
- 2022
- Full Text
- View/download PDF
36. Revision of the Massarineae(Pleosporales, Dothideomycetes)
- Author
-
Tanaka, K., Hirayama, K., Yonezawa, H., Sato, G., Toriyabe, A., Kudo, H., Hashimoto, A., Matsumura, M., Harada, Y., Kurihara, Y., Shirouzu, T., and Hosoya, T.
- Abstract
We here taxonomically revise the suborder Massarineae(Pleosporales, Dothideomycetes, Ascomycota). Sequences of SSU and LSU nrDNA and the translation elongation factor 1-alpha gene (tef1) are newly obtained from 106 Massarineaetaxa that are phylogenetically analysed along with published sequences of 131 taxa in this suborder retrieved from GenBank. We recognise 12 families and five unknown lineages in the Massarineae. Among the nine families previously known, the monophyletic status of the Dictyosporiaceae, Didymosphaeriaceae, Latoruaceae, Macrodiplodiopsidaceae, Massarinaceae, Morosphaeriaceae, and Trematosphaeriaceaewas strongly supported with bootstrap support values above 96 %, while the clades of the Bambusicolaceaeand the Lentitheciaceaeare moderately supported. Two new families, Parabambusicolaceaeand Sulcatisporaceae, are proposed. The Parabambusicolaceaeis erected to accommodate Aquastromaand Parabambusicolagenera nova, as well as two unnamed Monodictysspecies. The Parabambusicolaceaeis characterised by depressed globose to hemispherical ascomata with or without surrounding stromatic tissue, and multi-septate, clavate to fusiform, hyaline ascospores. The Sulcatisporaceaeis established for Magnicamarosporiumand Sulcatisporagenera nova and Neobambusicola. The Sulcatisporaceaeis characterised by subglobose ascomata with a short ostiolar neck, trabeculate pseudoparaphyses, clavate asci, broadly fusiform ascospores, and ellipsoid to subglobose conidia with or without striate ornamentation. The genus Periconiaand its relatives are segregated from the Massarinaceaeand placed in a resurrected family, the Periconiaceae. We have summarised the morphological and ecological features, and clarified the accepted members of each family. Ten new genera, 22 new species, and seven new combinations are described and illustrated. The complete ITS sequences of nrDNA are also provided for all new taxa for use as barcode markers.
- Published
- 2015
- Full Text
- View/download PDF
37. Statistical characterization of the foremoon particle and wave morphology: ARTEMIS observations
- Author
-
Harada, Y., Halekas, J. S., Poppe, A. R., Tsugawa, Y., Kurita, S., and McFadden, J. P.
- Abstract
Although the zeroth‐order picture of the Moon‐solar wind interaction involves no upstream perturbation, the presence of the Moon does affect the upstream plasma in a variety of ways. In this paper, a large volume of data obtained by the dual‐probe Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) mission are used to characterize the large‐scale morphology of the “foremoon,” which is defined as the region upstream of the Moon and its wake that contains Moon‐related particles and waves. Solar wind ions reflected from the unshielded surface and by crustal magnetic fields, together with heavy ions of lunar surface/exospheric origin, are picked up by the solar wind magnetic and electric fields. Partially coinciding with populations of these Moon‐related ions, ∼0.01 Hz and ∼1 Hz magnetic field fluctuations are observed. The morphology of the Moon‐related ion and wave distributions is well organized by the upstream magnetic field direction. In addition, the low‐frequency wave distributions depend on the upstream Alfvén Mach numbers, suggesting that propagation effects also play a role in determining the wave foremoon morphology. Occurrence of modified electron velocity distributions and higher‐frequency, electromagnetic, and electrostatic waves is primarily controlled by magnetic connection to the Moon and its wake. These statistical results observationally demonstrate the large‐scale properties of the foremoon and upstream‐parameter control thereof. ARTEMIS observes a wide variety of lunar upstream particles and wavesGlobal distributions of lunar upstream phenomena are organized by IMF directionLow‐frequency wave distributions are controlled by Mach numbers
- Published
- 2015
- Full Text
- View/download PDF
38. Histological and immunohistological analysis of degenerative changes in the cranial cruciate ligament in a canine model of excessive tibial plateau angle
- Author
-
Ichinohe, T., Kanno, N., Harada, Y., Yogo, T., Tagawa, M., and Hara, Y.
- Published
- 2015
- Full Text
- View/download PDF
39. Ultrasound-guided gradual reduction using flexion and abduction continuous traction for developmental dysplasia of the hip
- Author
-
Fukiage, K., Futami, T., Ogi, Y., Harada, Y., Shimozono, F., Kashiwagi, N., Takase, T., and Suzuki, S.
- Abstract
We describe our experience in the reduction of dislocation of the hip secondary to developmental dysplasia using ultrasound-guided gradual reduction using flexion and abduction continuous traction (FACT-R). During a period of 13 years we treated 208 Suzuki type B or C complete dislocations of the hip in 202 children with a mean age of four months (0 to 11). The mean follow-up was 9.1 years (five to 16). The rate of reduction was 99.0%. There were no recurrent dislocations, and the rate of avascular necrosis of the femoral head was 1.0%. The rate of secondary surgery for residual acetabular dysplasia was 19.2%, and this was significantly higher in those children in whom the initial treatment was delayed or if other previous treatments had failed (p = 0.00045). The duration of FACT-R was significantly longer in severe dislocations (p = 0.001) or if previous treatments had failed (p = 0.018). This new method of treatment is effective and safe in these difficult cases and offers outcomes comparable to or better than those of standard methods.Cite this article: Bone Joint J 2015;97-B:405–11.
- Published
- 2015
- Full Text
- View/download PDF
40. Donor cell leukemia arising from preleukemic clones with a novel germline DDX41 mutation after allogenic hematopoietic stem cell transplantation
- Author
-
Kobayashi, S, Kobayashi, A, Osawa, Y, Nagao, S, Takano, K, Okada, Y, Tachi, N, Teramoto, M, Kawamura, T, Horiuchi, T, Kato, S, Maekawa, T, Yamamura, T, Watanabe, J, Harada, Y, Harada, H, Sato, K, and Kimura, F
- Published
- 2017
- Full Text
- View/download PDF
41. ARTEMIS observations of lunar dayside plasma in the terrestrial magnetotail lobe
- Author
-
Harada, Y., Machida, S., Halekas, J. S., Poppe, A. R., and McFadden, J. P.
- Abstract
We report observations by the dual‐probe Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) mission of Moon‐related electron and ion signatures obtained above the dayside lunar surface in the terrestrial magnetotail lobes. While the Moon is often thought of as a passive absorber, recent observations from Kaguya, Chandrayaan, Chang'E, and ARTEMIS indicate that plasma of lunar origin can have significant effects on the near‐lunar environment. We now present new observations from ARTEMIS showing that lunar plasma can play a dominant role in the low‐density environment of the terrestrial magnetotail. Two‐point observations reveal that the density of plasma of lunar origin is higher than that of the ambient lobe plasma even several hundreds of kilometers above the Moon's dayside. Meanwhile, the distributions of incoming electrons exhibit modifications correlated with Moon‐related populations, suggesting direct or indirect interactions of the lobe electrons with plasma of lunar origin. We also observe high‐energy photoelectron emission from the dayside lunar surface, supporting the existence of large positive potentials on the lunar surface. Pickup ions with nonzero parallel‐velocity components provide further evidence for positive surface potentials of tens of volts or more. ARTEMIS data reveal not only the existence of the positive surface potentials much larger than those predicted from a current‐balance model based on Maxwellian plasmas but also their significant implications for the dynamics of both the dominant Moon‐originating ions and the tenuous ambient plasma populations in the tail lobe. Large positive potentials exist on the dayside lunar surfacePlasma of lunar origin dominates the tail lobe plasmaLunar plasma modifies ambient electron velocity distributions
- Published
- 2013
- Full Text
- View/download PDF
42. Clinical efficacy of autogenous cancellous bone and fibroblast growth factor 2 combined with frozen allografts in femoral nonunion fractures
- Author
-
Akagi, H., Ochi, H., Kannno, N., Iwata, M., Ichinohe, T., Harada, Y., Nezu, Y., Yogo, T., Tagawa, M., and Hara, Y.
- Published
- 2013
- Full Text
- View/download PDF
43. Fatigue Behavior of A5052 Aluminum Alloy with DLC/Thermally Sprayed WC-12Co Hybrid Coatings
- Author
-
Uematsu, Y., Kakiuchi, T., Kobayashi, Y., and Harada, Y.
- Abstract
Rotating bending fatigue tests had been performed using A5052 aluminum (Al) alloy with the hybrid coatings which consisted of tungsten carbide including 12% cobalt (WC-12Co) interlayer and diamond-like carbon (DLC) film, in order to investigate the effect of hybrid coating on the fatigue behavior. The WC-12Co layer was thermally sprayed by a high velocity oxygen fuel (HVOF) method on A5052 with the thickness of 70, 120 or 170μm. Subsequently, the DLC film was deposited with the thickness of 15μm. The fatigue strengths of the specimens with WC-12Co single layer were higher than those of the substrate and increased with increasing the thickness of WC-12Co layer. The fatigue strengths of the specimens with the hybrid coating of 70μm WC-12Co interlayer and 15μm DLC film were better than those of the specimen with 70μm WC-12Co single layer. Thus the hybrid coating structure was effective to improve fatigue strengths. However the beneficial effect of hybrid coating was not apparent in the specimens with thicker WC-12Co interlayer of 120 and 170μm.
- Published
- 2012
- Full Text
- View/download PDF
44. Spectral intensities and phase distributions of supercontinuum pulses generated in low-dispersion fibers
- Author
-
Sone, H., Yoshitomi, D., Zhou, X., Kikuchi, K., Kasahara, R., Abrishamian, F., Nakamura, S., Harada, Y., and Torizuka, K.
- Abstract
It was reported recently that optical pulses propagating through a tapered fiber (TF) immersed in heavy water (D2O) or photonic crystal fiber (PCF) of special design yield a broad and flat supercontinuum (SC) spectrum because the fiber dispersion characteristics are of low dispersion: around 1000 nm. This work was undertaken to investigate spectral intensities and phase distributions of SC pulses generated in low-dispersion fibers. Results show that PCF with group velocity dispersion (GVD) distributions having an extremum value of zero dispersion can be used at short fiber length for applications where the phase distribution is a concern.
- Published
- 2011
- Full Text
- View/download PDF
45. Si 2p Core Level Shifts of the Epitaxial SiON Layer on a SiC(0001), Studied by Photoemissin Spectroscopy
- Author
-
Shirasawa, T., Tanaka, S., Muro, T., Tamenori, Y., Harada, Y., Tokushima, T., Kinoshita, T., Shin, S., Takahashi, T., and Tochihara, H.
- Abstract
The epitaxial silicon oxynitride (SiON) layer grown on a 6H-SiC(0001) surface is studied with core level photoemission spectroscopy. Si 2p spectra show three spectral components other than the bulk one. Chemical shifts and emission angle dependence of these components are well explained within a framework of a determined structure model of the SiON layer.
- Published
- 2011
- Full Text
- View/download PDF
46. A class-wide phylogenetic assessment of Dothideomycetes
- Author
-
Schoch, C.L., Crous, P.W., Groenewald, J.Z., Boehm, E.W.A., Burgess, T.I., de Gruyter, J., de Hoog, G.S., Dixon, L.J., Grube, M., Gueidan, C., Harada, Y., Hatakeyama, S., Hirayama, K., Hosoya, T., Huhndorf, S.M., Hyde, K.D., Jones, E.B.G., Kohlmeyer, J., Kruys, Å., Li, Y.M., Lücking, R., Lumbsch, H.T., Marvanová, L., Mbatchou, J.S., McVay, A.H., Miller, A.N., Mugambi, G.K., Muggia, L., Nelsen, M.P., Nelson, P., Owensby, C.A., Phillips, A.J.L., Phongpaichit, S., Pointing, S.B., Pujade-Renaud, V., Raja, H.A., Plata, E. Rivas, Robbertse, B., Ruibal, C., Sakayaroj, J., Sano, T., Selbmann, L., Shearer, C.A., Shirouzu, T., Slippers, B., Suetrong, S., Tanaka, K., Volkmann-Kohlmeyer, B., Wingfield, M.J., Wood, A.R., Woudenberg, J.H.C., Yonezawa, H., Zhang, Y., and Spatafora, J.W.
- Abstract
We present a comprehensive phylogeny derived from 5 genes, nucSSU, nucLSU rDNA, TEF1, RPB1and RPB2, for 356 isolates and 41 families (six newly described in this volume) in Dothideomycetes. All currently accepted orders in the class are represented for the first time in addition to numerous previously unplaced lineages. Subclass Pleosporomycetidaeis expanded to include the aquatic order Jahnulales.An ancestral reconstruction of basic nutritional modes supports numerous transitions from saprobic life histories to plant associated and lichenised modes and a transition from terrestrial to aquatic habitats are confirmed. Finally, a genomic comparison of 6 dothideomycete genomes with other fungi finds a high level of unique protein associated with the class, supporting its delineation as a separate taxon.
- Published
- 2009
- Full Text
- View/download PDF
47. Molecular taxonomy of bambusicolous fungi: Tetraplosphaeriaceae, a new pleosporalean family with Tetraploa-like anamorphs
- Author
-
Tanaka, K., Hirayama, K., Yonezawa, H., Hatakeyama, S., Harada, Y., Sano, T., Shirouzu, T., and Hosoya, T.
- Abstract
A new pleosporalean family Tetraplosphaeriaceaeis established to accommodate five new genera; 1) Tetraplosphaeriawith small ascomata and anamorphs belonging to Tetraploa s. str., 2) Triplosphaeriacharacterised by hemispherical ascomata with rim-like side walls and anamorphs similar to Tetraploabut with three conidial setose appendages, 3) Polyplosphaeriawith large ascomata surrounded by brown hyphae and anamorphs producing globose conidia with several setose appendages, 4) Pseudotetraploa, an anamorphic genus, having obpyriform conidia with pseudosepta and four to eight setose appendages, and 5) Quadricrura, an anamorphic genus, having globose conidia with one or two long setose appendages at the apex and four to five short setose appendages at the base. Fifteen new taxa in these genera mostly collected from bamboo are described and illustrated. They are linked by their Tetraploa s. l.anamorphs. To infer phylogenetic placement in the Pleosporales, analyses based on a combined dataset of small- and large-subunit nuclear ribosomal DNA (SSU+LSU nrDNA) was carried out. Tetraplosphaeriaceae, however, is basal to the main pleosporalean clade and therefore its relationship with other existing families was not completely resolved. To evaluate the validity of each taxon and to clarify the phylogenetic relationships within this family, further analyses using sequences from ITS-5.8S nrDNA (ITS), transcription elongation factor 1-α (TEF), and β-tubulin (BT), were also conducted. Monophyly of the family and that of each genus were strongly supported by analyses based on a combined dataset of the three regions (ITS+TEF+BT). Our results also suggest that Tetraplosphaeria(anamorph: Tetraploa s. str.) is an ancestral lineage within this family. Taxonomic placement of the bambusicolous fungi in Astrosphaeriella, Kalmusia, Katumotoa, Massarina, Ophiosphaerella, Phaeosphaeria, Roussoella, Roussoellopsis, and Versicolorisporium, are also discussed based on the SSU+LSU phylogeny.
- Published
- 2009
- Full Text
- View/download PDF
48. Influence of IOP Measurement through the Wrong Eyepiece of the Slit Lamp on Goldmann Applanation Tonometry
- Author
-
Kubota, T., Nagata, T., Tawara, A., Okada, H., Ishibashi, S., Yamashita, M., Harada, Y., and Yanase, M.
- Abstract
Purpose This study examined whether intraocular pressure (IOP) measurements through the wrong eyepiece of the slit lamp may be a source of error.Methods Seven skilled observers measured the IOP from seven healthy subjects. The observers used a Haag-Streit Goldmann applanation tonometer with two types of slit lamps (Haag-Streit and Rodenstock). In the Haag-Streit slit lamp the prism of the tonometer is aligned with the right part of the slit lamp optics. Conversely in the Rodenstock slit lamp, the prism is aligned with the left. Each observer measured the IOP of each subject through the right eyepiece, through the left eyepiece, and under binocular vision.Results The IOP measured with the left eyepiece of the Haag-Streit slit lamp was significantly higher than that measured with the right eyepiece and binocular vision. The IOP measured with the right eyepiece of the Rodenstock slit lamp was significantly higher than that measured with the left eyepiece and binocular vision.Conclusions IOP measurement through the wrong eyepiece of the slit lamp may be a source of error.
- Published
- 2008
- Full Text
- View/download PDF
49. The characteristics of dorsal-root ganglia and sensory innervation of the hip in rats
- Author
-
Nakajima, T., Ohtori, S., Inoue, G., Koshi, T., Yamamoto, S., Nakamura, J., Takahashi, K., and Harada, Y.
- Abstract
Using a rat model the characteristics of the sensory neurones of the dorsal-root ganglia (DRG) innervating the hip were investigated by retrograde neurotransport and immunohistochemistry.Fluoro-Gold solution (FG) was injected into the left hip of ten rats. Seven days later the DRG from both sides between T12 and L6 were harvested. The number of FG-labelled calcitonin gene-related peptide-immunoreactive or isolectin B4-binding neurones were counted.The FG-labelled neurones were distributed throughout the left DRGs between T13 and L5, primarily at L2, L3, and L4. Few FG-labelled isolectin B4-binding neurones were present in the DRGs of either side between T13 and L5, but calcitonin gene-related peptide-immunoreactive neurones made up 30% of all FG-labelled neurones.Our findings may explain the referral of pain from the hip to the thigh or lower leg corresponding to the L2, L3 and L4 levels. Since most neurones are calcitonin gene-related peptide-immunoreactive peptide-containing neurones, they may have a more significant role in the perception of pain in the hip as peptidergic DRG neurones.
- Published
- 2008
- Full Text
- View/download PDF
50. Testing Method for Heat Resistance Under Temperature Gradient
- Author
-
Takagi, K., Kawasaki, A., Itoh, Y., Harada, Y., and Ono, F.
- Abstract
Abstract: “Testing Method for Heat Resistance under Temperature Gradient” is a Japanese Industrial Standard (JIS) newly established by the Minister of Economy, Trade and Industry, after deliberations by the Japanese Industrial Standards Committee, in accordance with the Industrial Standardization Law. This standard specified the testing method for heat resistance under temperature gradient of materials and coated members of equipment exposed to high temperature, such as aircraft engines, gas turbines, and so on. This paper introduces the principle and overview of the established standard. In addition, taking the heat cycle test using the burner rig for instance, we specifically illustrate the acquirable data and their analysis in the standard. Monitoring of the effective thermal conductivity and acoustic emission particularly enables to the non-destructive evaluation of failure cycle.
- Published
- 2007
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.