Investigation of charged particle intensity during the flights of the second and third space-ships

Ginzburg, V. L.; Kurnosova, L. V.; Logachev, V. I.; Rozarenov, L.A.; Sirotkin, I.A.; Fradkin, M. I.

doi:10.1016/0032-0633(62)90113-7

Cited by 17 publications

(4 citation statements)

References 2 publications

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“…Figure la shows four such orbits, further details of which will be found in Table 1. The oval shape sketched on the map in Figure la gives some indication of the region in which the background counting rate has been found to be high by previous workers (see for example, Ginzburg et al [1962], and the reviews by Vernov et aL [1967], Paulikas [1975], Gledhill [1976], and Voss and Smith [1980]). The portions of orbits shown by thicker lines are those from which the data were subjected to the integration process.…”

Section: Ae-c Datamentioning

confidence: 81%

Nighttime observations of 0.2‐ to 26‐keV electrons in the South Atlantic Anomaly made by Atmosphere Explorer C

Gledhill¹,

Hoffman²

1981

J. Geophys. Res.

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The high-energy background radiation in the South Atlantic Anomaly makes it difficult to measure the fluxes and spectra of the low-energy particles with any degree of certainty, and as a result no values for the energy range below 30 keV are to be found in the literature. We have found that the flux of lowenergy ions is much smaller than that of the electrons. This has enabled us to use the low-energy ion detector on AE-C to monitor the high-energy background and to correct the response of the low-energy electron detector for this. The electron spectra can be represented by a power law in the range 0.2-26 keV, with the spectral index close to -1. Maps are shown of downward energy flux in this range over the South Atlantic Anomaly. The mean energy flux carried by electrons in the middle of the anomaly is found to be about 3 x 10 -3 erg cm -2 s -• and may reach 5 times this value on occasions. A surprising result is that this energy flux decreases as Kp increases.

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Section: Ae-c Datamentioning

confidence: 81%

Nighttime observations of 0.2‐ to 26‐keV electrons in the South Atlantic Anomaly made by Atmosphere Explorer C

Gledhill¹,

Hoffman²

1981

J. Geophys. Res.

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“… 1960 ; Vernov and Chudakov 1960 ; Ginzburg et al. 1962 ). It has been well documented over the intervening years as a region of geospace where satellites systematically experience an enhanced radiation dose (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…The South Atlantic Anomaly (SAA) was originally detected by early low-earth satellite missions in the late 1950s as a region of enhanced flux of energetic charged particles (Yoshida et al 1960;Vernov and Chudakov 1960;Ginzburg et al 1962). It has been well documented over the intervening years as a region of geospace where satellites systematically experience an enhanced radiation dose (e.g.…”

Section: Introductionmentioning

confidence: 99%

The CHAOS-7 geomagnetic field model and observed changes in the South Atlantic Anomaly

Finlay

Kloss

Olsen

et al. 2020

Earth Planets Space

212

206

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We present the CHAOS-7 model of the time-dependent near-Earth geomagnetic field between 1999 and 2020 based on magnetic field observations collected by the low-Earth orbit satellites Swarm, CryoSat-2, CHAMP, SAC-C and Ørsted, and on annual differences of monthly means of ground observatory measurements. The CHAOS-7 model consists of a time-dependent internal field up to spherical harmonic degree 20, a static internal field which merges to the LCS-1 lithospheric field model above degree 25, a model of the magnetospheric field and its induced counterpart, estimates of Euler angles describing the alignment of satellite vector magnetometers, and magnetometer calibration parameters for CryoSat-2. Only data from dark regions satisfying strict geomagnetic quiet-time criteria (including conditions on IMF $$B_z$$ B z and $$B_y$$ B y at all latitudes) were used in the field estimation. Model parameters were estimated using an iteratively reweighted regularized least-squares procedure; regularization of the time-dependent internal field was relaxed at high spherical harmonic degree compared with previous versions of the CHAOS model. We use CHAOS-7 to investigate recent changes in the geomagnetic field, studying the evolution of the South Atlantic weak field anomaly and rapid field changes in the Pacific region since 2014. At Earth’s surface a secondary minimum of the South Atlantic Anomaly is now evident to the south west of Africa. Green’s functions relating the core–mantle boundary radial field to the surface intensity show this feature is connected with the movement and evolution of a reversed flux feature under South Africa. The continuing growth in size and weakening of the main anomaly is linked to the westward motion and gathering of reversed flux under South America. In the Pacific region at Earth’s surface between 2015 and 2018 a sign change has occurred in the second time derivative (acceleration) of the radial component of the field. This acceleration change took the form of a localized, east–west oriented, dipole. It was clearly recorded on ground, for example at the magnetic observatory at Honolulu, and was seen in Swarm observations over an extended region in the central and western Pacific. Downward continuing to the core–mantle boundary, we find this event originated in field acceleration changes at low latitudes beneath the central and western Pacific in 2017.

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“…An additional candidate mechanism that could lead to the appearance of T in < 0 is related to the South Atlantic Anomaly (SAA), the region over the South Atlantic Ocean where the magnetic field strength is significantly weaker than in other parts of the planet (Vernov and Chudakov, 1960;Yoshida et al, 1960;Ginzburg et al, 1962): the low altitude of the mirroring point of energetic particles in this region leads to enhanced fluxes of precipitating high-energy ions and electrons that are higher than at other longitudes. This leads to enhanced collisions with the neutrals, and since the early days of space exploration it has been speculated that this can lead to the deposition of a significant amount of energy to the neutral atmosphere.…”

Section: Possible Physical Mechanisms That Could Lead To Observations...mentioning

confidence: 99%

Analysis of in situ measurements of electron, ion and neutral temperatures in the lower thermosphere–ionosphere

Pirnaris,

Sarris

2023

Ann. Geophys.

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Abstract. Simultaneous knowledge of the temperatures of electrons, ions and neutrals is key to the understanding and quantification of energy transfer processes in planetary atmospheres. However, whereas electron and ion temperature measurements are routinely obtained from ground-based incoherent scatter radars, simultaneous measurements of electron, ion and neutral temperature measurements can only be made in situ. For the Earth's lower thermosphere–ionosphere, the only available comprehensive in situ dataset of electron, ion and neutral temperatures to date is that of the Atmosphere Explorers C, D and E and the Dynamics Explorer 2 missions. In this study we first perform a cross-comparison of all co-temporal and co-spatial measurements between in situ electron and ion temperature measurements from the above in situ spacecraft missions with corresponding measurements from the Arecibo, Millstone Hill and Saint-Santin incoherent scatter radars, during times of overflights of these spacecraft over the radar fields of view. This expands upon a previous study that only considered data from the Atmosphere Explorer C. The results indicate good agreement between satellite and ground-based radar measurements. Subsequently, out of the above datasets, all instances where ion temperatures appear to be lower than neutral temperatures are identified and are studied statistically. Whereas current understanding indicates that ion temperatures are generally expected to be higher than neutral temperatures in the lower thermosphere–ionosphere, a non-negligible number of events is found where this does not hold true. The distribution of all such cases in altitude, latitude and longitude is presented and discussed. Potential causes leading to neutral temperatures being higher than ion temperatures are outlined, including both instrumental effects or measurement errors and physical causes. Whereas a conclusive case cannot be made based on the present analysis, it is speculated from the results presented herein that not all cases can be attributed to instrument effects or measurement errors. This can have significant implications for the current understanding that the energy of the ions is expected to be higher than that of the neutrals and points to the need for additional simultaneous in situ measurements in the lower thermosphere–ionosphere (LTI).

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Investigation of charged particle intensity during the flights of the second and third space-ships

Cited by 17 publications

References 2 publications

Nighttime observations of 0.2‐ to 26‐keV electrons in the South Atlantic Anomaly made by Atmosphere Explorer C

Nighttime observations of 0.2‐ to 26‐keV electrons in the South Atlantic Anomaly made by Atmosphere Explorer C

The CHAOS-7 geomagnetic field model and observed changes in the South Atlantic Anomaly

Analysis of in situ measurements of electron, ion and neutral temperatures in the lower thermosphere–ionosphere

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