The inner magnetosphere ion composition and local time distribution over a solar cycle

2016 ◽  
Vol 121 (3) ◽  
pp. 2009-2032 ◽  
Author(s):  
L. M. Kistler ◽  
C. G. Mouikis
Keyword(s):  
Solar Cycle ◽  
Local Time ◽  
Time Distribution ◽  
Ion Composition ◽  
Inner Magnetosphere

scholarly journals Cluster observation of few-hour-scale evolution of structured plasma in the inner magnetosphere

2013 ◽  
Vol 31 (9) ◽  
pp. 1569-1578 ◽  
Author(s):  
M. Yamauchi ◽  
I. Dandouras ◽  
H. Rème ◽  
R. Lundin ◽  
L. M. Kistler
Keyword(s):  
Local Time ◽  
Trapped Ions ◽  
Low Energy ◽  
Local Times ◽  
Significant Enhancement ◽  
Occurrence Rate ◽  
Wide Energy Range ◽  
Inner Magnetosphere ◽  
Wide Energy ◽  
Cluster Ion

Abstract. Using Cluster Ion Spectrometry (CIS) data from the spacecraft-4 perigee traversals during the 2001–2006 period (nearly 500 traversals after removing those that are highly contaminated by radiation belt particles), we statistically examined the local time distribution of structured trapped ions at sub- to few-keV range as well as inbound–outbound differences of these ion signatures in intensities and energy–latitude dispersion directions. Since the Cluster orbit during this period was almost constant and approximately north–south symmetric at nearly constant local time near the perigee, inbound–outbound differences are attributed to temporal developments in a 1–2 h timescale. Three types of structured ions at sub- to few keV range that are commonly found in the inner magnetosphere are examined: – Energy–latitude dispersed structured ions at less than a few keV, – Short-lived dispersionless ion stripes at wide energy range extending 0.1–10 keV, – Short-lived low-energy ion bursts at less than a few hundred eV. The statistics revealed that the wedge-like dispersed ions are most often observed in the dawn sector (60% of traversals), and a large portion of them show significant enhancement during the traversals at all local times. The short-lived ion stripes are predominantly found near midnight, where most stripes are significantly enhanced during the traversals and are associated with substorm activities with geomagnetic AL < −300 nT. The low-energy bursts are observed at all local times and under all geomagnetic conditions, with moderate peak of the occurrence rate in the afternoon sector. A large portion of them again show significant enhancement or decay during the traversals.

scholarly journals The Scalable Plasma Ion Composition and Electron Density (SPICED) Model for Earth's Inner Magnetosphere

2021 ◽  
Vol 126 (9) ◽  
Author(s):  
Matthew K. James ◽  
Tim K. Yeoman ◽  
Petra Jones ◽  
Jasmine K. Sandhu ◽  
Jerry Goldstein
Keyword(s):  
Electron Density ◽  
Ion Composition ◽  
Inner Magnetosphere

scholarly journals Ozone and temperature decadal solar-cycle responses, and their relation to diurnal variations in the stratosphere, mesosphere, and lower thermosphere, based on measurements from SABER on TIMED

2019 ◽  
Vol 37 (4) ◽  
pp. 471-485 ◽  
Author(s):  
Frank T. Huang ◽  
Hans G. Mayr
Keyword(s):  
Solar Cycle ◽  
Local Time ◽  
Satellite Data ◽  
Diurnal Cycle ◽  
Lower Thermosphere ◽  
Diurnal Variations ◽  
Local Times ◽  
Data Set ◽  
Orbital Drift ◽  
Almost All

Abstract. There is evidence that the ozone and temperature responses to the solar cycle of ∼11 years depend on the local times of measurements. Here we present relevant results based on SABER data over a full diurnal cycle, which were not previously available. In this area, almost all satellite data used are measured at only one or two fixed local times, which can differ among various satellites. Consequently, estimates of responses can be different depending on the specific data set. Furthermore, over years, due to orbital drift, the local times of the measurements of some satellites have also drifted. In contrast, SABER makes measurements at various local times, providing the opportunity to estimate diurnal variations over 24 h. We can then also estimate responses to the solar cycle over both a diurnal cycle and at the fixed local times of specific satellite data for comparison. Responses derived in this study, based on zonal means of SABER measurements, agree favorably with previous studies based on data from the HALOE instrument, which only measured data at sunrise and sunset, thereby supporting the analysis of both studies. We find that for ozone above ∼40 km, zonal means reflecting specific local times (e.g., 6, 12, 18, 24 LST – local solar time) lead to different values of responses, and to different responses based on zonal means that are also averages over the 24 h local time period, as in 3-D models. For temperature, the effects of diurnal variations on the responses are not negligible even at ∼30 km and above. We also considered the consequences of local time variations due to orbital drifts of certain operational satellites, and, for both ozone and temperature, their effects can be significant above ∼30 km. Previous studies based on other satellite data do not describe the treatment, if any, of local times. Some studies also analyzed data merged from different sources, with measurements made at different local times. Generally, the results of these studies do not agree very well among themselves. Although responses are a function of diurnal variations, this is not to say that they are the major reason for the differences, as there are likely other data-related issues. The effects due to satellite orbital drift may explain some unexpected variations in the responses, especially above 40 km.

Titan’s Ultraviolet Airglow Variability with Solar Cycle and Saturn Local Time

2020 ◽  
Author(s):  
Emilie Royer ◽  
Marielle Cooper ◽  
Joseph Ajello ◽  
Larry Esposito ◽  
Frank Crary
Keyword(s):  
Solar Cycle ◽  
Local Time ◽  
Solar Maximum ◽  
Incidence Angle ◽  
Upper Atmosphere ◽  
Particle Precipitation ◽  
Cassini Mission ◽  
Airglow Emissions ◽  
Airglow Intensity

&lt;p&gt;The Cassini spacecraft observed Titan&amp;#8217;s upper atmosphere and its airglow emissions from 2005 to 2017. It is now established that the solar XUV radiation is the main source of dayglow, while magnetospheric particle precipitation principally acts on the nightside of the satellite. Nevertheless, one of the questions remaining unanswered after the end of the Cassini mission concerns the role and quantification of the magnetospheric particle precipitation and other minor sources such as micrometeorite precipitation and cosmic galactic ray at Titan. We report here on enhancements observed in Ultraviolet (UV) observations of Titan airglow made with the Cassini-Ultraviolet Imaging Spectrograph (UVIS). Enhancements are correlated with magnetospheric changing conditions occurring while the spacecraft, and thus Titan, are known to have crossed Saturn&amp;#8217;s magnetopause and have been exposed to the magnetosheath environment. The processing and interpretation of 13+ years of airglow observations at Titan allows now for global studies of the upper atmosphere as a function of the Saturn Local Time (SLT) and the solar cycle.&lt;/p&gt;&lt;p&gt;Nitrogen airglow occur at about 1100 km of altitude in Titan&amp;#8217;s upper atmosphere. Observations by the Cassini-UVIS instrument revealed the emission of the LBH band system, VK band system as well as Nitrogen atomic emission lines at 1085&amp;#197; and 1493&amp;#197;, as the prominent features of airglow emissions at Titan, as shown in Figures 1 and 2. Measurements were made at a wide range of solar incidence angles and Saturn Local Time (SLT), during the entire Cassini mission, allowing for the investigation of the upper atmosphere response to the magnetospheric environment and energetic particle precipitation. Additionally, observations were taken in a variety of solar condition, from solar maximum to minimum. UVIS observations of Titan around 12PM SLT (near Saturn&amp;#8217;s magnetopause) present evidence of Titan&amp;#8217;s upper atmosphere response to a fluctuating magnetospheric environment.&lt;/p&gt;&lt;p&gt;&lt;img src=&quot;https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.9617eca672fe56938492951/sdaolpUECMynit/0202CSPE&amp;app=m&amp;a=0&amp;c=975f92d7d9d43faa47cacd77ad47438f&amp;ct=x&amp;pn=gnp.elif&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Figure 1.&lt;/strong&gt; Airglow intensity as a function of the saturn Local Time (SLT), for observation taken close the Saturn&amp;#8217;s magnetopause (12PM SLT, labelled &amp;#8216;12h&amp;#8217;) and observations taken around miadnight SLT (labelled &amp;#8216;24h&amp;#8217;). Dayglow spectra exhibit higher averaged airglow intensity than Nightglow spectra.&lt;/p&gt;&lt;p&gt;We present here comparisons of the spectral emissions from the dayglow (Solar incidence angle &lt;110&amp;#176;) and nightglow (Solar incidence angle &amp;#8805;110&amp;#176;) between a rayheight of 900-1200 km around noon (&amp;#177;1 h) and around midnight (&amp;#177;1 h) SLT, during solar minima and maxima conditions (Fig. 2). Results show an enhancement of the airglow brightness with increasing particle precipitation, especially at SLT close to noon (i.e. close to the magnetopause), during solar maximum and minimum. Correlation between the ratio of the V-K, LBH, and NI-1493&amp;#197; emission peaks are also presented.&lt;/p&gt;&lt;p&gt;&lt;img src=&quot;https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.2357e48772fe52168492951/sdaolpUECMynit/0202CSPE&amp;app=m&amp;a=0&amp;c=2c6d843782e300fc27ec3db3de320caf&amp;ct=x&amp;pn=gnp.elif&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Figure 2.&lt;/strong&gt; Dayglow intensity as a function of the saturn Local Time (SLT) and solar cycle. Observations have been dispatched in four groups as a function of Titan&amp;#8217;s orbital position within Saturn&amp;#8217;s magnetosphere and maximum oe minimum stage of the solar cycle. Results suggest that solar maximum conditions around midgnight SLT favor the apparition of the brightest dayglow.&lt;/p&gt;&lt;p&gt;In the past decade, results from the Cassini-UVIS instrument greatly improved our understanding of airglow production at Titan. However, combining remote-sensing datasets, such as Cassini-UVIS data, with in-situ measurements taken by the Cassini Plasma Spectrometer (CAPS) instrument can provide us with a more rigorous assessment of the airglow contribution and correlations between data from simultaneous observations of in-situ Cassini instruments (CAPS, RPWS and MIMI) has been possible on few occasions. UVIS results present here will be put in context with results from in-situ simultaneous observations.&lt;/p&gt;&lt;!-- COMO-HTML-CONTENT-END --&gt; &lt;p class=&quot;co_mto_htmlabstract-citationHeader&quot;&gt; &lt;strong class=&quot;co_mto_htmlabstract-citationHeader-intro&quot;&gt;How to cite:&lt;/strong&gt; Royer, E., Cooper, M., Ajello, J., Esposito, L., and Crary, F.: Titan&amp;#8217;s Ultraviolet Airglow Variability with Solar Cycle and Saturn Local Time, Europlanet Science Congress 2020, online, 21 September&amp;#8211;9 Oct 2020, EPSC2020-415, 2020 &lt;/p&gt;

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