Pitch Angle Data Research Articles

Retraction Statement: New Types of Electron Pitch Angle Distributions on Mars: Funnel and Skirt Distrbiutions

Retraction: Guo, Z. et al. (2023). New types of electron pitch angle distributions on Mars: Funnel and skirt distributions. Geophysical Research Letters, 50, e2022GL101874, https://doi.org/10.1029/2022GL101874. The above article, published online on 24 January 2023 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors; the journal Editor‐in‐Chief, Harihar Rajaram; American Geophysical Union; and John Wiley and Sons Ltd. The retraction has been agreed because the electron pitch angle data presented were contaminated by internally produced photoelectrons as a result of the illumination geometry of the sensor at the time of the observations. After removal of the affected angular bins by the instrument principal investigator, the published conclusions were found to be invalid. Therefore, the paper was retracted at the request of the authors.

A Coronal Mass Ejection and Magnetic Ejecta Observed In Situ by STEREO-A and Wind at 55° Angular Separation

We present an analysis of in situ and remote-sensing measurements of a coronal mass ejection (CME) that erupted on 2021 February 20 and impacted both the Solar TErrestrial RElations Observatory (STEREO)-A and the Wind spacecraft, which were separated longitudinally by 55°. Measurements on 2021 February 24 at both spacecraft are consistent with the passage of a magnetic ejecta (ME), making this one of the widest reported multispacecraft ME detections. The CME is associated with a low-inclined and wide filament eruption from the Sun’s southern hemisphere, which propagates between STEREO-A and Wind around E34. At STEREO-A, the measurements indicate the passage of a moderately fast (∼425 km s−1) shock-driving ME, occurring 2–3 days after the end of a high speed stream (HSS). At Wind, the measurements show a faster (∼490 km s−1) and much shorter ME, not preceded by a shock nor a sheath, and occurring inside the back portion of the HSS. The ME orientation measured at both spacecraft is consistent with a passage close to the legs of a curved flux rope. The short duration of the ME observed at Wind and the difference in the suprathermal electron pitch-angle data between the two spacecraft are the only results that do not satisfy common expectations. We discuss the consequence of these measurements on our understanding of the CME shape and extent and the lack of clear signatures of the interaction between the CME and the HSS.

Design of the Synthetic Aperture Microwave Imager Upgrade for measurement of the edge current density on MAST-U

The Synthetic Aperture Microwave Imager (SAMI) has demonstrated the feasibility of 2D Doppler backscattering for measurement of the edge magnetic pitch angle on MAST and NSTX-U. The aim of SAMI-Upgrade (SAMI-U) is to build on this methodology to produce higher quality pitch angle data simultaneously in multiple spatial locations, enabling calculation of the edge current density. This movement from proof of principle to production quality necessitates several alterations to the design. There will be a fourfold increase in the number of antennas, as minimising the sidelobe level is key to ensuring maximum resolution in the reconstructed Doppler backscattered power map. SAMI-U will actively probe the plasma with two frequencies at the same time. These correspond to two different backscattering locations in the edge plasma which allows the edge current density to be calculated from the measured magnetic field vector. Dual-polarised sinuous antennas will be used in the array as they are planar and broadband. Polarisation separation is necessary for differentiation between the O-and X-mode cut off surfaces, as their locations can be separated by up to a few centimetres. Due to spatial constraints many of the components will be placed on a PCB behind each antenna. FPGAs will be used to stream the high data throughput, over 16 GB s−1, into PC memory.

THE HYDRO PLANING SIMULATION OF FLYING BOAT REMOTE CONTROL MODEL

The measurement of unknown model to get the three dimensions of object configuration is by using the laser camera photo tracking. The three dimensions model became from solid drawing on the CATIA software. The CFX ANSYS computational fluid dynamics software is used on the 3D of Flying Boat remote control model full configuration. The rectangular and dihedral configurations of the model have Z forces value during acceleration on the water surface. The pressure distributions hydro planing have a good result also. The speeds on the simulation model are around (0 - 25) knots and Angle of Attack, α = 00. The downwash effect and vortex could be shown in the CFD results. To verify the simulation data analysis is uses the takeoff flight performance testing data during takeoff of Unmanned Aerial Vehicle “Alap alap” with the same Thrust per Weight ratio around 0.4, such as altitude height, airspeed, Z acceleration and pitch angle data. The hump drag of Flying Boat remote control model and the friction during takeoff of Unmanned Aerial Vehicle have been ignored.

Correction to “Pc2 EMIC waves generated high off the equator in the dayside outer magnetosphere”

[1] The paper “Pc2 EMIC waves generated high off the equator in the dayside outer magnetosphere” by Y. Liu et al. (Geophys. Res. Letters, 39, L17102, doi:10.1029/2012GL053082, 2012) reported an electromagnetic ion cyclotron (EMIC) wave event detected by the four Cluster spacecraft from ~0820 to ~1400 UT on 16 February 2004, which is believed to be the first observational evidence of EMIC wave activity in the local minimum magnetic field region off the equator. Such a location has been predicted as an EMIC wave source region in previous theoretical work involving Shabansky particle orbits and drift shell splitting [McCollough et al., 2010, 2012]. H+ energy and pitch angle spectra from the Cluster Ion Spectrometry (CIS)-Composition and Distribution Function (CODIF) Analyzer [Rème et al., 2001] onboard Cluster 1 (C1), shown in the bottom two panels of Figure 2 by Liu et al. [2012], are used to confirm that the EMIC waves were locally excited. However, the plotted CODIF H+ energy spectra data from the ESA Cluster Active Archive obtained for the Liu et al. [2012] study some 2 years ago are erroneous and not consistent with the actual data plots now available on the ESA Cluster Active Archive. A CODIF instrument anomaly resulted in unusual features in the H+ pitch angle spectra that were not revealed in the paper. Consequently, descriptions of the plasma properties during the wave event shown in the bottom panel in Figure 2 of Liu et al. [2012] over times before 1029 UT and after 1230 UT are incorrect. Between these two times the pitch angle data are correct. During the event, CODIF on C1 experienced an increase in the high-voltage current across the microchannel plate detectors [Rème et al., 2001]. This type of high-voltage anomaly, taking place a few times throughout the year of 2004, resulted in the complete switch-off of the instrument on 29 October 2004. [2] In this correction, we present the more reliable ion measurements from the other instrument in the CIS package, the Hot Ion Analyzer (HIA), on the same Cluster spacecraft C1. The new results are presented below. It is important to point out that the original conclusions arrived at by Liu et al. [2012] in their summary section are in no way affected by the incorrect plasma data originally published, namely that the source of this wave event in the outer magnetosphere is located off the geomagnetic equator. [3] On Cluster the CODIF sensor measures ion composition, and the HIA sensor measures all ions [Rème et al., 2001]. Figure 1 shows the Cluster/CIS-HIA plasma measurements on C1 in the same period as Figure 2 by Liu et al. [2012], i.e., 0800–1430 UT on 16 February 2004. The top panel shows the HIA ion energy-time flux spectrogram and the bottom panel the pitch angle-time flux spectrogram, both for the full energy range 5.56 eV to 28.90 keV. Data are missing from 1325 UT on the plot, and the vertical magenta dotted lines indicate the start (0820 UT) and end (1400 UT) time of the wave event. The pitch angle observations centered on 90° on the horizontal black dotted line indicates that the strong temperature anisotropies of hot (>10 keV) ions are the likely direct cause of the EMIC wave activity. [4] Research at the UoN was supported by Australian Research Council Discovery Project grant DP0772504 and Linkage International grant LX0882515. Work at PRIC was supported by the Ocean Public Welfare Scientific Research Project (201005017) and the Shanghai Pujiang Talent Project (12PJ1409200). Work at UNH was supported by NASA under grant numbers NNX11AO82G and NNX11AB65G. The authors thank C. G. Mouikis and other Cluster team members for Cluster data preparation and software development.

2P2-C09 らせん路登坂における傾斜センサを用いた軌道誘導(移動ロボットの自己位置推定と地図構築)

The spiral radius of a trajectory is most useful information to navigate a mobile robot in traveling on a spiral slope. The measurement method of this spiral radius has not been revealed yet. This paper describes the measurement method by some calculation of robot inclination sensor data. The spiral radius is related to the maximum inclination angle of a spiral slope and the maximum inclination angle can be detected by the combination of roll angle and pitch angle data. The experiment of the trajectory control on a spiral slope using the detected spiral radius is achieved successfully.

Characteristic boundary transitions in energetic particle data (60– ≥ 260 keV) recorded at comets P/Grigg-Skjellerup and P/Halley by the EPONA instrument on Giotto

An overview of published magnetic field, low energy electron and low to intermediate energy ion data recorded on board Giotto during an encounter with P/Grigg-Skjellerup (G-S) on 10 July, 1992 is presented and these measurements compared with particle data secured by the onboard energetic particles experiment EPONA ( E = 60 to ≥260 keV). It is shown that, in general, the same cometary boundaries (Bow Wave, Bow Shock, Mystery Boundary Transitions (MBTs)) were sensed in energetic particles as by the other experiments. Elevated fluxes of accelerated particles, interpreted to be ions of species M = 16–18, were identified in the G-S cometosheath. It is inferred that heavy cometary ions of species M = 28–33 were present in the innermost region of the comet (as viewed in the sunward direction). Energetic particles recorded by EPONA on Giotto at P/Halley are considered relative to other particles and fields measurements obtained onboard. Evidence based on pitch angle data indicates that, inbound, the MBTs at G-S and at Halley, were spatially associated with changes from trapped to “flowing” distributions of water group ions, suggesting that mirroring of these particles was taking place during encounter in the magnetic field piled up around each comet. Downstream of the MBTs, outbound, flowing distributions were, in each case, identified. Evidence of MBTs in energetic particle data are, herein, reported for the first time. The roles of various mechanisms in accelerating cometary ions in association with Bow Wave/Bow Shock boundaries at G-S and at Halley are inferred from comparisons between experimental and theoretical spectra pertinent to each comet. Similarities and differences between the signatures of characteristic boundaries recorded in each case are discussed in the light of basic differences between the comets themselves, and between the ambient interplanetary circumstances pertaining during each cometary encounter.

Equilibrium q-profile determination and stability analysis from magnetic field pitch angle measurements using motional Stark effect polarimetry

The motional Stark effect polarimetry technique has been used to measure the magnetic pitch angle in a variety of PBX-M plasma conditions. For high aspect ratio, circular plasmas, the q profile can be obtained directly from the γp profile using the cylindrical expression q(r)=(rBT/RBp). In strongly shaped PBX-M plasmas, the magnetic pitch angle data are used as an internal constraint on the plasma equilibrium calculated by solving the Grad–Shafranov equation, subject to external flux measurements. Thus, an accurate determination of q(r) depends upon detailed knowledge of the plasma equilibrium. Discussion of uncertainties in the equilibrium determination and their effect on q(r) will be presented. The equilibrium solutions using the pitch angle data are required for MHD stability calculations, which are being used to investigate the relationship between internal kink modes and plasma shape.

Longitudinal structure of substorm injections at synchronous orbit

From multiple‐spacecraft measurements it is shown that the synchronous orbit manifestation of a substorm, i.e., plasma injection and magnetic field reconfiguration to dipolar, has an onset which expands both eastward and westward from a relatively narrow sector near midnight. For low‐to‐moderate geomagnetic activity the earliest onset sector at synchronous orbit is about 3 hours wide, skewed toward the evening side of midnight. Using the extensive International Magnetospheric Study ground magnetometer network beneath the satellites, it is found that simultaneous westward motion of electrojet intensification is seen in the ground data over a larger longitudinal range than the magnetospheric signatures. This might be explained in terms of distortion of the nightside magnetic field at synchronous orbit. Plasma that has already been injected near midnight at synchronous altitude undergoes no further change as a result of the westward and eastward motion of the borders of the plasma. This suggests that the expansion does not represent new substorm activation. One can interpret these results in terms of an injection front wedge which makes hot plasma accessible to the inner magnetosphere and which spatially expands or propagates with time. The origin of plasma behind the front is not addressed. Detailed pitch angle data do, however, show that strong precipitation would be expected from the front for about the first 10 min after the front passes over an observer. Finally, as a result of longitudinal expansion of plasma injections from midnight toward evening or morning and the continuation or even enhancement of field inflation in the evening or morning sectors, growth and expansive phase substorm signatures can occur simultaneously. Substorm expansion at midnight can thus be accompanied by continued growth signatures in evening or morning.

On the configuration of the magnetotail near midnight during quiet and weakly disturbed periods: Magnetic field modeling

Energetic‐particle pitch angle data and vector magnetometer data, measured along the Ogo 5 inbound orbit near midnight on three magnetically quiet days, August 2, 4, and 25, 1968, were used to infer the magnetic tail field configuration for each day. For the first 2 days the particles, when initially detected, showed isotropic pitch angle distributions (PAD's) (indicative of nonadiabatic motions resulting from the breakdown of the guiding center invariants µ and J) but later made rapid transitions to the butterfly PAD (indicative of adiabatic guiding center motion). The lower‐rigidity particles made the PAD transitions first and were followed in turn by the higher‐rigidity particles as Ogo neared the earth. We have used a simple algebraic model which has allowed us to fit both the magnetic field and the pitch angle transition data. For the latter data fit, the detailed particle trajectories were followed along the model field lines to the neutral sheet. The particles were required to execute adiabatic guiding center motion if they were started from positions on the satellite orbit nearer earth than the point of observed changes in the PAD. They were required to undergo nonadiabatic motion at some part of their trajectory if they were started at a point on the satellite orbit farther from the earth than the PAD transition point. The results are presented in terms of model coefficients for each day. The model fields are plotted, the cross‐tail currents are derived, and particle motion is studied in the model fields. It was found that 79‐keV electrons were in the nonadiabatic mode when they were on field lines that crossed the neutral sheet beyond 11 RE on August 2; on August 25, a less taillike day, this point was 17 ± 1 RE. For 10‐keV protons the inferred points are 8.5 and 11.7 RE, respectively, for these 2 days. This is interesting because protons of about this energy carry a large part of the cross‐tail current. It is expected that when data from particles of a wide range of rigidity are available, this method of inferring the tail field configuration should be very powerful.

On the configuration of the magnetotail near midnight during quiet and weakly disturbed periods: State of the magnetosphere

Energetic‐electron pitch angle data and magnetic field data obtained on inbound passes of Ogo 5 in 1968 near midnight during quiet periods have been studied. From observation of the vector field components along the orbit and knowledge of the satellite position when the pitch angle distributions changed from approximate isotropy (indicating non‐guiding center particle motion) to the butterfly distribution (corresponding to adiabatic bounce orbits) the configuration of the near‐earth tail field for individual orbits has been inferred. The details of the modeling are presented in a companion paper. We find that quasi‐steady field configurations near midnight can occur that are markedly different (ranging from taillike to fairly dipolelike) in different cases, even though the usual magnetic activity indicators (Kp, AE, auroral zone and mid‐latitude magnetograms, and BZGSM of the interplanetary magnetic field) differ but slightly from one case to another and indicate a quiet magnetosphere. The major differences in the data are that more intense lobe fields occur at the same distance down the tail for the more taillike field configurations (∼30 γ at 15 RE for taillike configurations and ∼15 γ at 15 RE for more dipolelike configurations). There appears to be evidence that the more taillike configuration is associated with an enhanced dynamic pressure from the solar wind. The data, viewed in the light of previously published data obtained by the present experimenters and others, argue strongly that during quiet times the plasma sheet, in its azimuthal variation, is at its thinnest in the region near midnight. These results affect current ideas of the substorm growth phase and the evolution of energetic‐electron pitch angle distributions in the postmidnight magnetosphere.

Energetic electrons in the inner belt in 1968

Pitch-angle data were obtained by the Lawrence Livermore Laboratory's scanning, magnetic electron spectrometer on OGO 5 during its traversals of the inner belt in 1968. Data from the five lowest-energy channels 79–822 keV, were analyzed in terms of j ⊥ vs λ I, time-decay rates, and spectral shapes at constant L. The inner-belt electron injection following two storm periods was observed; the first was the mild storm of 11 June and the second the more intense storms of 31 October and 1 November. Comparisons with other data indicate that only a small Starfish residual (at > 1 MeV) still remained in the heart of the inner belt; hence, the results are indicative of the normal inner belt. The data are discussed in terms of current ideas regarding the source and loss of particles in the inner belt.

Drift mirror instability in the magnetosphere: Particle and field oscillations and electron heating

The published L = 5 equatorial magnetosphere particle and field data from the April 18, 1965, geomagnetic storm are reanalyzed in the context of the drift mirror instability theory developed by Hasegawa. These data, together with previously unpublished electron pitch-angle data, are shown to satisfy the requirements and consequences of the instability. Additional particle data observed during a 1967 substorm by an experiment on ATS 1 are also presented to show that the observation of the April 18 instability was not an isolated occurrence in the magnetosphere. The data also contain evidence for electron heating during the time of the instability.