Yuki Harada

Kyoto University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

J. S. Halekas

University of Iowa

G. A. DiBraccio

Goddard Space Flight Center

D. L. Mitchell

University of California, Berkeley

J. R. Espley

Goddard Space Flight Center

D. A. Brain

University of Colorado Boulder

B. M. Jakosky

Laboratory for Atmospheric and Space Physics

Takuya Hara

University of California, Berkeley

S. Ruhunusiri

University of Iowa

J. P. McFadden

University of California, Berkeley

J. E. P. Connerney

Goddard Space Flight Center

Cooperative Institutions

Centre National de la Recherche Scientifique

121

Laboratory for Atmospheric and Space Physics

107

Goddard Space Flight Center

University of Colorado Boulder

University of California, Berkeley

Planetary Science Institute

Institute of Space and Astronautical Science

Japan Aerospace Exploration Agency

University of Michigan–Ann Arbor

John Wiley & Sons (United States)

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Acknowledgement of Reviewers for 2023

Surveys in Geophysics (2024)

D. P. Chambers Julien Chaojian Chen Cheng Chen Fubin Chen Huaizhen

Acknowledgement

10.1007/s10712-024-09823-1

Cite

Citations (0)

Marsward and tailward ions in the near‐Mars magnetotail: MAVEN observations

Geophysical Research Letters (2015)

Yuki Harada J. S. Halekas J. P. McFadden D. L. Mitchell C. Mazelle

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.

Atmosphere of Mars

Exosphere

10.1002/2015gl065005

Cite

Citations (39)

Global Maps of Solar Wind Electron Modification by Electrostatic Waves Above the Lunar Day Side: Kaguya Observations

Geophysical Research Letters (2021)

Yuki Harada Yoshiya Kasahara Masaki N. Nishino Satoshi Kurita Y. Saito

Abstract The Moon drives observable perturbations in the upstream solar wind in a similar manner to the terrestrial foreshock. Recent observations suggested that lunar dayside electrostatic waves can arise from two different driving mechanisms, both involving reflected particles from lunar crustal magnetic fields. However, their association with the global distribution of lunar magnetic anomalies have not been fully characterized. Here we exploit polar orbiting Kaguya to generate first global maps of electrostatic waves and solar wind electron modification above the day side of the Moon. The maps clearly demonstrate that the two signatures are correlated with lunar crustal magnetic fields. Additionally, we observe different characteristics of electron modification for different interplanetary magnetic field orientations. The lunar crustal magnetic fields cause a wide range of reflected electron and ion intensities, thereby serving as a test bed to investigate the relative roles of reflected particles on wave excitation and particle heating.

10.1029/2021gl095260

Cite

Citations (3)

Does the presence of a friend reduce cardiovascular response to stress even over a screen?

PLoS ONE (2024)

Ayumi Kambara Hisashi Mitsuishi Yuki Harada

Although meeting close friends through video calls has become common, less is known about its stress-buffering effect. This study aims to examine whether cardiovascular responses to stress are decreased when the presence of a friend on a monitor compared to the presence of a friend in person or alone. Forty-six undergraduate students completed a stress task while in the room with a friend (1) in person (in-person condition), (2) on Zoom (online condition), or (3) alone (alone condition). Blood pressure and heart rate were monitored throughout the experiment. Analyses revealed that diastolic blood pressure after the stress was recovered closer to the pre-stress state under in-person and online conditions than alone condition. However, the study observed no differences across groups regarding self-reported affect. In summary, this result suggests that even the online presence of a friend, as well as in-person friends, may help recover blood pressure to the original state without one’s awareness.

Affect

10.1371/journal.pone.0314562

Cite

Citations (0)

Particles and Photons as Drivers for Particle Release from the Surfaces of the Moon and Mercury

Space Science Reviews (2022)

P. Wurz S. Fatemi André Galli J. S. Halekas Yuki Harada

Abstract The Moon and Mercury are airless bodies, thus they are directly exposed to the ambient plasma (ions and electrons), to photons mostly from the Sun from infrared range all the way to X-rays, and to meteoroid fluxes. Direct exposure to these exogenic sources has important consequences for the formation and evolution of planetary surfaces, including altering their chemical makeup and optical properties, and generating neutral gas exosphere. The formation of a thin atmosphere, more specifically a surface bound exosphere, the relevant physical processes for the particle release, particle loss, and the drivers behind these processes are discussed in this review.

Exosphere

Mercury

Planetary science

Particle (ecology)

10.1007/s11214-022-00875-6

Cite

Citations (32)

Photoemission and electrostatic potentials on the dayside lunar surface in the terrestrial magnetotail lobes

Geophysical Research Letters (2017)

Yuki Harada A. R. Poppe J. S. Halekas Phillip C. Chamberlin J. P. McFadden

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.

10.1002/2017gl073419

Cite

Citations (16)

Reflected Protons in the Lunar Wake and Their Effects on Wake Potentials

Journal of Geophysical Research Space Physics (2020)

Shaosui Xu A. R. Poppe J. S. Halekas Yuki Harada

Abstract The refilling of the lunar wake is facilitated by the wake ambipolar electric potential arising from the electron pressure gradient. Incident solar wind protons can be reflected by the lunar crustal magnetic fields and the lunar surface on the dayside and repicked up, entering the lunar wake due to their large gyroradii. This burst of positive charges can cause the lunar wake potential to be reduced by hundreds of volts. We utilize over 7 years of ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun) measurements to systematically investigate how the reflected protons affect the lunar wake potential structure when the Moon is immersed in the solar wind. RPs have a peak occurrence rate of ∼20% for downstream distances from the Moon at N ×2 π R g and a preference of high occurrence rates and high densities in the direction of the motional electric field of the solar wind. We show that reflected protons in the lunar wake can significantly change the electrostatic ambipolar potentials in the wake, leading in turn to the formation of field‐aligned, accelerated electron beams. Our case study also suggests a nonmonotonic field‐aligned potential structure in the presence of reflected protons in the wake. Lastly, our results show that when the reflected proton density is larger than ∼30% of the local proton density from refilling solar wind protons, the wake potential scales as the logarithmic density of reflected protons, which can be explained by the Boltzmann relation.

Ambipolar diffusion

10.1029/2020ja028154

Cite

Citations (8)

Electrons on closed field lines of lunar crustal fields in the solar wind wake

Icarus (2014)

Masaki N. Nishino Y. Saito Hideo Tsunakawa Futoshi Takahashi M. Fujimoto

10.1016/j.icarus.2014.12.007

Cite

Citations (8)

Spatiotemporal Characteristics of 360-Degree Basic Attention

Scientific Reports (2019)

Yuki Harada Junji Ohyama

Abstract The spatiotemporal characteristics of basic attention are important for understanding attending behaviours in real-life situations, and they are useful for evaluating the accessibility of visual information. However, although people are encircled by their 360-degree surroundings in real life, no study has addressed the general characteristics of attention to 360-degree surroundings. Here, we conducted an experiment using virtual reality technology to examine the spatiotemporal characteristics of attention in a highly controlled basic visual context consisting of a 360-degree surrounding. We measured response times and gaze patterns during the 360-degree search task and examined the spatial distribution of attention and its temporal variations in a 360-degree environment based on the participants’ physical position. Data were collected from both younger adults and older adults to consider age-related differences. The results showed the fundamental spatiotemporal characteristics of 360-degree attention, which can be used as basic criteria to analyse the structure of exogenous effects on attention in complex 360-degree surroundings in real-life situations. For practical purposes, we created spherical criteria maps of 360-degree attention, which are useful for estimating attending behaviours to 360-degree environmental information or for evaluating visual information design in living environments, workspaces, or other real-life contexts.

Degree (music)

Work space

10.1038/s41598-019-52313-3

Cite

Citations (7)

A reconsideration of the lunar wake boundary based on Kaguya (SELENE) observations

EGUGA (2018)

Masaki N. Nishino Y. Saito Hideo Tsunakawa Yuki Harada Shoichiro Yokota

Source

Cite

Citations (0)