In situ magnetotail magnetic flux calculation

Shukhtina, M. A.; Gordeev, E.

doi:10.5194/angeo-33-769-2015

Cited by 4 publications

(7 citation statements)

References 23 publications

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“… Abbreviations of models: PR96 [ Petrinec and Russell , ], KS98 [ Kuznetsov and Suvorova , ], P98 [ Pudovkin et al , ], S98 [ Shue et al , ], B00 [ Boardsen et al , ], L10 [ Lin et al , ], W13 [ Wang et al , ], and SG15 [ Shukhtina and Gordeev , ].…”

Section: Empirical and Numerical Modelsmentioning

confidence: 99%

“…The model has no predetermined analytical form, and consequently, its results for any given condition cannot be reproduced without full access to the model. Shukhtina and Gordeev [] (SG15) developed a model to determine the magnetopause position at the terminator plane in the high‐latitude regions as a function of P dyn , B z , and Ψ.…”

Section: Empirical and Numerical Modelsmentioning

confidence: 99%

“…Since Fairfield [], more than 15 empirical magnetopause models have been developed (14 of them mentioned in Suvorova and Dmitriev []) which define the magnetopause using different sets of observations. However, with only several exceptions [ Dmitriev and Suvorova , ; Wang et al , ; Shukhtina and Gordeev , ], all the empirical models made some a priori assumptions about the magnetopause shape. For example, the well‐known Shue et al [] model assumed the functional form

R = R_{x} {((), \frac{2}{1 + \cos θ})}^{α}

for the magnetopause, where R is the radial distance, R x is the position of the subsolar point, and θ is the solar zenith angle.…”

Section: Introductionmentioning

confidence: 99%

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Do we know the actual magnetopause position for typical solar wind conditions?

et al. 2016

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We compare predicted magnetopause positions at the subsolar point and four reference points in the terminator plane obtained from several empirical and numerical MHD models. Empirical models using various sets of magnetopause crossings and making different assumptions about the magnetopause shape predict significantly different magnetopause positions (with a scatter >1 RE) even at the subsolar point. Axisymmetric magnetopause models cannot reproduce the cusp indentations or the changes related to the dipole tilt effect, and most of them predict the magnetopause closer to the Earth than nonaxisymmetric models for typical solar wind conditions and zero tilt angle. Predictions of two global nonaxisymmetric models do not match each other, and the models need additional verification. MHD models often predict the magnetopause closer to the Earth than the nonaxisymmetric empirical models, but the predictions of MHD simulations may need corrections for the ring current effect and decreases of the solar wind pressure that occur in the foreshock. Comparing MHD models in which the ring current magnetic field is taken into account with the empirical Lin et al. model, we find that the differences in the reference point positions predicted by these models are relatively small for Bz=0. Therefore, we assume that these predictions indicate the actual magnetopause position, but future investigations are still needed.

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Section: Empirical and Numerical Modelsmentioning

confidence: 99%

Section: Empirical and Numerical Modelsmentioning

confidence: 99%

R = R_{x} {((), \frac{2}{1 + \cos θ})}^{α}

for the magnetopause, where R is the radial distance, R x is the position of the subsolar point, and θ is the solar zenith angle.…”

Section: Introductionmentioning

confidence: 99%

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Do we know the actual magnetopause position for typical solar wind conditions?

et al. 2016

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“…In Shukhtina et al [] we developed the PR96 approach such that the magnetopause radius and the corresponding MTF value F 0 are computed using magnetotail and solar wind measurements for each particular time. In Shukhtina and Gordeev [, hereafter SG'15] two modifications of the method, F 1 and F 2 , suitable in the inner magnetosphere, were introduced. In section 2 we overview all three estimates, after which we present their calibration and validation (the main goal of this paper).…”

Section: Introductionmentioning

confidence: 99%

Magnetotail magnetic flux monitoring based on simultaneous solar wind and magnetotail observations

et al. 2016

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The magnetotail magnetic flux (MTF) is an important global variable to describe the magnetospheric state and dynamics. Existing methods of MTF estimation on the basis of the polar cap area, inferred from observations of global auroras and field‐aligned currents, do not allow benchmarking due to the absence of a gauge for comparison; besides, they rarely allow a systematic nearly real time MTF monitoring. We describe three modifications (F0, F1, and F2) of the method to calculate the MTF, based on simultaneous spacecraft observations in the magnetotail and in the solar wind, suitable for real‐time MTF monitoring. The MTF dependence on the solar wind parameters and the observed tail lobe magnetic field is derived from the pressure balance conditions. An essential part of this study is the calibration of our approximate method against global 3‐D MHD simulations and the empirical T14 magnetospheric field model. The calibration procedure provides all variables required to evaluate F0, F1, and F2 quantities and, at the same time, computes the reference MTF value through any tail cross section. It allowed us to extend the method to be used in the near tail, investigate its errors, and define the applicability domain. The method was applied to Cluster and THEMIS measurements and compared with methods of polar cap area calculation based on IMAGE and AMPERE observations. We also discuss possible applications and some recent results based on the proposed method.

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“…As mentioned earlier, the shape of the MP is asymmetric due to the cusp regions. We, therefore, used models with an analytical formula, taking into account the pressure imbalance due to the Earth's dipole tilt angle ( ) that reproduces the cusp regions resulting in an asymmetric MP shape (Lin et al, 2010;Shukhtina & Gordeev, 2015). Zhong et al (2014) have shown that the Earth's dipole moment has been decaying over the past 1.5 centuries.…”

Section: Data and Analysismentioning

confidence: 99%

Beyond the Minisolar Maximum of Solar Cycle 24: Declining Solar Magnetic Fields and the Response of the Terrestrial Magnetosphere

Ingale

Janardhan

2019

JGR Space Physics

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The present study examines the response of the terrestrial magnetosphere to the long‐term steady declining trends observed in solar magnetic fields and solar wind microturbulence levels since mid‐1990s that has been continuing beyond the minisolar maximum of cycle 24. A detailed analysis of the response of the terrestrial magnetosphere has been carried out by studying the extent and shape of the Earth's magnetopause and bow shock over the past four solar cycles. We estimate subsolar stand‐off distance of the magnetopause and bow shock and the shape of the magnetopause, using numerical as well as empirical models. The computed magnetopause and bow shock stand‐off distances have been found to be increasing steadily since around mid‐1990s, consistent with the steady declining trend seen in solar magnetic fields and solar wind microturbulence levels. Similarly, we find an expansion in the shape of the magnetopause since 1996. The implications of the increasing trend seen in the magnetopause and bow shock stand‐off distances are discussed and a forecast of the shape of the magnetopause in 2020, the minimum of cycle 24, has been made. Importantly, we also find two instances between 1968 and 1991 when the magnetopause stand‐off distance dropped to values close to 6.6 Earth radii, the geostationary orbit, for duration ranging from 9–11 hr and one event in 2005, post 1995 when the decline in photospheric fields began. Though there have been no such events since 2005, it represents a clear and present danger to our satellite systems.

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In situ magnetotail magnetic flux calculation

Cited by 4 publications

References 23 publications

Do we know the actual magnetopause position for typical solar wind conditions?

Do we know the actual magnetopause position for typical solar wind conditions?

Magnetotail magnetic flux monitoring based on simultaneous solar wind and magnetotail observations

Beyond the Minisolar Maximum of Solar Cycle 24: Declining Solar Magnetic Fields and the Response of the Terrestrial Magnetosphere

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