Subauroral electron temperature enhancement in the nighttime ionosphere

Abstract. In the nightside subauroral region, heat transfer from the ring current causes a significant increase in the electron temperature of the upper ionosphere. Using DE-2 satellite data, we investigate the properties of this remarkable feature. We find that the location of the temperature enhancement is primarily dependent on the level of geomagnetic activity. For geomagnetically quiet conditions ()the temperature peak is located slightly poleward of 60° invariant latitude. For each decrease in the Dst index by 10 nT, it moves equatorward by about one degree. To a lesser degree, the location of the heating effect also depends on magnetic local time, with a significant positional asymmetry about midnight. The magnitude of the temperature enhancement varies with altitude. Within the height range 280 to 940 km, the peak temperature increases by 73%, on average. Thereby a conspicuous increase in the temperature gradient is observed above about 700km altitude. The magnitude of the heating effect also depends on the level of geomagnetic activity. For a decrease in the Dst index by 100 nT, the peak temperature increases by 46%, on average. This rate of increase, however, depends on season and is significantly smaller during winter conditions. A superposed epoch type of averaging procedure is used to obtain mean latitudinal profiles of the temperature enhancement. For an altitude of 500 km, the following mean properties are derived: amplitude K; width at half this peak value deg; distance between equatorward boundary and maximum deg. On average, a decrease in the electron density is observed at the location of the temperature enhancement, at least at 500 km altitude. At the same time, a moderate increase in the zonal ion drift speed is recorded at this location. During larger geomagnetic storms, the latitudinal profile of the temperature enhancement assumes a more step-function-like shape, with a broad increase in electron temperature poleward from the equatorial edge of the electron temperature enhancement. Also the heating effects may extend to very low latitudes (less than 35° invariant latitude). And residual heating effects are observed long after the storm-substorm activity has ceased. The results obtained in this study should prove useful for both empirical and theoretical modeling of the nightside subauroral ionosphere.

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Investigating seasonal features of electron temperature enhancement regions in the subauroral ionosphere

Solnechno-Zemnaya Fizika ◽

10.12737/szf-51201909 ◽

2019 ◽

Vol 5 (1) ◽

pp. 82-89

Author(s):

Артем Гололобов ◽

Artem Gololobov ◽

Иннокентий Голиков ◽

Innokentiy Golikov

Keyword(s):

Numerical Simulation ◽

Electron Temperature ◽

Geomagnetic Activity ◽

Universal Time ◽

Geomagnetic Disturbances ◽

Champ Satellite ◽

Main Ionospheric Trough ◽

Different Seasons ◽

Temperature Enhancement

The electron temperature enhancement is known to occur in the main ionospheric trough during geomagnetic disturbances. In this paper, we study fea-tures of the formation of the electron temperature (Te) enhancement in the subauroral ionosphere by comparing results of the numerical simulation with measurements of Te onboard the CHAMP satellite under moderate geomagnetic activity conditions. It is shown that depending on the terminator position and universal time (UT), the location of the enhanced Te regions in the subauroral ionosphere varies in different seasons. So, in winter ring-shaped and sickle-shaped regions can be formed, whereas during the equinox and summer periods sickle-shaped regions of different lengths and clarity are generally observed.

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Investigating seasonal features of electron temperature enhancement regions in the subauroral ionosphere

Solar-Terrestrial Physics ◽

10.12737/stp-51201909 ◽

2019 ◽

Vol 5 (1) ◽

pp. 62-68

Author(s):

Артем Гололобов ◽

Artem Gololobov ◽

Иннокентий Голиков ◽

Innokentiy Golikov

Keyword(s):

Numerical Simulation ◽

Electron Temperature ◽

Geomagnetic Activity ◽

Universal Time ◽

Geomagnetic Disturbances ◽

Champ Satellite ◽

Main Ionospheric Trough ◽

Different Seasons ◽

Temperature Enhancement

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In situ observation of electron temperature enhancement inside equatorial plasma bubbles

10.3997/2214-4609-pdb.168.arq_2006 ◽

2003 ◽

Author(s):

P. Muralikrishna

Keyword(s):

Electron Temperature ◽

In Situ Observation ◽

Plasma Bubbles ◽

Equatorial Plasma Bubbles ◽

Temperature Enhancement

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Electron temperature in nighttime sporadic E layer at mid-latitude

Annales Geophysicae ◽

10.5194/angeo-26-533-2008 ◽

2008 ◽

Vol 26 (3) ◽

pp. 533-541 ◽

Cited By ~ 8

Author(s):

K.-I. Oyama ◽

T. Abe ◽

H. Mori ◽

J. Y. Liu

Keyword(s):

Heat Source ◽

Electron Temperature ◽

Physical Parameter ◽

Langmuir Probe ◽

Present Theory ◽

Height Range ◽

Neutral Temperature ◽

Sporadic E Layer ◽

Sporadic E ◽

Parameter Values

Abstract. Electron temperature in the sporadic E layer was measured with a glass-sealed Langmuir probe at a mid-latitude station in Japan in the framework of the SEEK (Sporadic E Experiment over Kyushu)-2 campaign which was conducted in August 2002. Important findings are two fold: (1) electron temperature and electron density vary in the opposite sense in the height range of 100–108 km, and electron temperature in the Es layer is lower than that of ambient plasma, (2) electron temperature in these height ranges is higher than the possible range of neutral temperature. These findings strongly suggest that the heat source that elevates electron temperature much higher than possible neutral temperature exists at around 100 km, and/or that the physical parameter values, which are used in the present theory to calculate electron temperature, are not proper.

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Analysis of the geomagnetic activity of the <i>D<sub>st</sub></i> index and self-affine fractals using wavelet transforms

Nonlinear Processes in Geophysics ◽

10.5194/npg-11-303-2004 ◽

2004 ◽

Vol 11 (3) ◽

pp. 303-312 ◽

Cited By ~ 19

Author(s):

H. L. Wei ◽

S. A. Billings ◽

M. Balikhin

Keyword(s):

Brownian Motion ◽

Geomagnetic Activity ◽

Power Law ◽

Wavelet Transforms ◽

Effective Measure ◽

Dst Index ◽

Power Spectral ◽

Power Law Exponent ◽

Brownian Motion Model

Abstract. The geomagnetic activity of the Dst index is analyzed using wavelet transforms and it is shown that the Dst index possesses properties associated with self-affine fractals. For example, the power spectral density obeys a power-law dependence on frequency, and therefore the Dst index can be viewed as a self-affine fractal dynamic process. In fact, the behaviour of the Dst index, with a Hurst exponent H≈0.5 (power-law exponent β≈2) at high frequency, is similar to that of Brownian motion. Therefore, the dynamical invariants of the Dst index may be described by a potential Brownian motion model. Characterization of the geomagnetic activity has been studied by analysing the geomagnetic field using a wavelet covariance technique. The wavelet covariance exponent provides a direct effective measure of the strength of persistence of the Dst index. One of the advantages of wavelet analysis is that many inherent problems encountered in Fourier transform methods, such as windowing and detrending, are not necessary.

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Full Field Joule Heating Measurement of Copper Plate Using Phase Shifting Moire´ Interferometry in Microscopic Scale

ASME 2009 InterPACK Conference, Volume 1 ◽

10.1115/interpack2009-89014 ◽

2009 ◽

Author(s):

Bicheng Chen ◽

Cemal Basaran

Keyword(s):

Joule Heating ◽

Current Density ◽

Moiré Interferometry ◽

Phase Shifting ◽

Moire Interferometry ◽

Heating Effect ◽

Full Field ◽

Microscopic Scale ◽

Joule Heating Effect ◽

Heating Effects

Heat generated from Joule heating is an important factor in several failure mechanisms in microelectronic packaging (e.g. thermomigration, electromigration and etc) and large amount of the heat causes severe heat dissipation problem. It is further exaggerated by the continuous marching towards miniaturization of microelectronics. The techniques of measuring the Joule heating effects at the microscopic scale are quite limited especially for the full field measurement. Infrared microscopic imaging has been reported to measure the heat radiation by the Joule heating in the microscopic scale. Moire´ interferometry with phase shifting is a highly sensitive and a high resolution method to measure the in-plane full field strain. In this paper, it is demonstrated that the Joule heating effect can be measured by Moire´ interferometry with phase shifting at the microscopic scale. The copper sheet is used for the demonstration because of isotropic material property and well known thermal properties and parameters. The specimen was designed to minimize the out-of-plane strain and the strain caused by the thermal-structural effects. A finite element model was developed to verify the design of the structure of the specimen and the specimen was tested under different current density (input current from 0 to 24 A). Based on the research, a correlation relationship between the current density and the strain in two orthogonal directions (one in the direction of the current flow) was determined. The regression coefficients of the full field were analyzed. The experiment demonstrates the capability of measuring microscopic Joule heating effects by using Moire´ interferometry with phase shifting. The method can be further applied to the measurement of Joule heating effect in the microscopic solid structures in the electronic packaging devices.

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The effect of electron bite-outs on artificial electron heating and the PMSE overshoot

Annales Geophysicae ◽

10.5194/angeo-23-3633-2005 ◽

2005 ◽

Vol 23 (12) ◽

pp. 3633-3643 ◽

Cited By ~ 25

Author(s):

M. Kassa ◽

O. Havnes ◽

E. Belova

Keyword(s):

Electron Temperature ◽

Electron Density ◽

Electron Density Profile ◽

Dust Particles ◽

High Electron ◽

Heating Effect ◽

Ion Temperature ◽

Degree Of Ionization ◽

Electron Heating ◽

Transmitter Power

Abstract. We have considered the effect that a local reduction in the electron density (an electron bite-out), caused by electron absorption on to dust particles, can have on the artificial electron heating in the height region between 80 to 90km, where noctilucent clouds (NLC) and the radar phenomenon PMSE (Polar Mesospheric Summer Echoes) are observed. With an electron density profile without bite-outs, the heated electron temperature Te,hot will generally decrease smoothly with height in the PMSE region or there may be no significant heating effect present. Within a bite-out Te,hot will decrease less rapidly and can even increase slightly with height if the bite-out is strong. We have looked at recent observations of PMSE which are affected by artificial electron heating, with a heater cycling producing the new overshoot effect. According to the theory for the PMSE overshoot the fractional increase in electron temperature Te,hot/Ti, where Ti is the unaffected ion temperature=neutral temperature, can be found from the reduction in PMSE intensity as the heater is switched on. We have looked at results from four days of observations with the EISCAT VHF radar (224 MHz), together with the EISCAT heating facility. We find support for the PMSE overshoot and heating model from a sequence of observations during one of the days where the heater transmitter power is varied from cycle to cycle and where the calculated Te,hot/Ti is found to vary in proportion to the transmitter power. We also looked for signatures of electron bite-outs by examining the variation of Te,hot/Ti with height for the three other days. We find that the height variation of Te,hot/Ti is very different on the three days. On one of the days we see typically that this ratio can increase with height, showing the presence of a bite-out, while on the next day the heating factor mainly decreases with height, indicating that the fractional amount of dust is low, so that the electron density is hardly affected by it. On the third day there is little heating effect on the PMSE layer. This is probably due to a sufficiently high electron density in the atmosphere below the PMSE layer, so that the transmitted heater power is absorbed in these lower layers. On this day the D-region, as given by the UHF (933MHz) observations, extends deeper down in the atmosphere than on the other two days, indicating that the degree of ionization in and below the PMSE layers is higher as well.

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A statistical study of the subauroral electron temperature enhancement using Dynamics Explorer 2 Langmuir probe observations

Journal of Geophysical Research Atmospheres ◽

10.1029/ja091ia10p11270 ◽

1986 ◽

Vol 91 (A10) ◽

pp. 11270 ◽

Cited By ~ 31

Author(s):

J. U. Kozyra ◽

L. H. Brace ◽

T. E. Cravens ◽

A. F. Nagy

Keyword(s):

Electron Temperature ◽

Langmuir Probe ◽

Statistical Study ◽

Temperature Enhancement

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Self-Heating Effects in SiGe Heterojunction Bipolar Transistor with Different Ge Grading Profile

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.l3486.1081219 ◽

2019 ◽

Vol 8 (12) ◽

pp. 3993-3999

Keyword(s):

Energy Balance ◽

Thermal Energy ◽

Power Dissipation ◽

Heterojunction Bipolar Transistor ◽

Heating Effect ◽

Sige Hbt ◽

Self Heating ◽

Heating Effects ◽

Local Temperature Increase ◽

Rf Performances

A comparative account of self heating effect of four SiGe HBTs with different Ge grading profiles, designated as Hybrid Trapezoidal (HT), Symmetrically Triangular (ST), Linear Increasing (LI), and Conventional Trapezoidal (CT) with maximum Ge contents of 20%, is presented. Based on an experimentally validated model of the Silvaco TCAD tool, the properties of the four HBTs are simulated. It is observed that both self heating and local temperature increase due to higher device power dissipation. The effect of energy balance and non iso thermal energy balance effect is observed in SiGe HBT with different Ge base profile have been studied in terms of DC, AC, and RF performances and compared .

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