Quantitative magnetotail characteristics of different magnetospheric states

Shukhtina, M. A.; Dmitrieva, N. P.; Сергеев, В. А.

doi:10.5194/angeo-22-1019-2004

Cited by 45 publications

(82 citation statements)

References 46 publications

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“…The BTF phase of delayed substorms can thus be viewed as the short-duration and low-AL extension of the SMC-like activity. One more significant quantitative difference is the average tail magnetic flux value during the BTF phase (0.72 GWb), considerably higher than <F SMC > = 0.57 GWb from DeJong et al [2007] and < F SMC > = 0.52 GWb obtained for given solar wind conditions by Shukhtina et al [2004] and shown in Figure 3. Compared to B Z numbers in the latter study the magnetotail configuration during BTF is more stressed compared to regular steady convection events.…”

Section: Discussion/concluding Remarksmentioning

confidence: 60%

“…For the first group, we selected 33 ideal substorms with monotonous flux increase from the quiet background with ΔF > 0.5 (< F onset > − < F SMC >). The statistical levels < F onset > and < F SMC > just before onset and during the steady magnetospheric convection (SMC) events were obtained by Shukhtina et al [2004] as a function of solar wind parameters. Typically, this threshold value was about 0.2 GWb.…”

Section: Discussionmentioning

confidence: 99%

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On the conditions preceding sudden magnetotail magnetic flux unloading

Shukhtina

Dmitrieva

Сергеев

2014

Geophysical Research Letters

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According to the substorm paradigm, the tail magnetic flux F is accumulated during the growth phase and suddenly released afterward. However, only 33 out of 142 isolated midtail sudden unloading events identified by Geotail in 1995-1998 demonstrated monotonous F increase (type 1 substorms). In 32 cases, balanced tail flux (BTF) period (F ∼constant) with enhanced dissipation and pseudobreakup activity during 0.5-2 h before unloading was registered (type 2, a new substorm class). The rest 77 substorms lie between types 1 and 2. Superposed epoch analysis revealed that during ∼40 min before unloading, both groups demonstrate almost identical plasma sheet thinning and B z decrease at Geotail. By the sudden unloading time, both groups have nearly identical B z values in the midtail as well as at 6.6 R E . We conclude that pre-onset midtail configuration changes are common for all substorm types irrespective of flux growth.

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Section: Discussion/concluding Remarksmentioning

confidence: 60%

Section: Discussionmentioning

confidence: 99%

On the conditions preceding sudden magnetotail magnetic flux unloading

Shukhtina

Dmitrieva

Сергеев

2014

Geophysical Research Letters

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“…We take advantage of exploiting the extensive data base of the merged solar wind and plasma sheet observations classified by different dynamical states, previously used to obtain the statistical regression models for the lobe magnetic field and tail flaring angle (also the tail radius and magnetic flux) as a function of solar wind parameters (Shukhtina et al, 2004), thereafter referred to as Paper 1. Referring to this paper for further details, we briefly review the data selection criteria.…”

Section: Data Base and Event Selectionmentioning

confidence: 99%

Average characteristics of the midtail plasma sheet in different dynamic regimes of the magnetosphere

2004

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Abstract.We study average characteristics of plasma sheet convection in the middle tail during different magnetospheric states (Steady Magnetospheric Convection, SMC, and substorms) using simultaneous magnetotail (Geotail, 15-35 R E downtail) and solar wind (Wind spacecraft) observations during 3.5 years.(1) A large data set allowed us to obtain the average values of the plasma sheet magnetic flux transfer rate (E y ) and directly compare it with the dayside transfer rate (E mod ) for different magnetospheric states. The results confirm the magnetic flux imbalance model suggested by Russell and McPherron (1973), namely: during SMC periods the day-to-night flux transport rate equals the global Earthward plasma sheet convection; during the substorm growth phase the plasma sheet convection is suppressed on the average by 40%, whereas during the substorm expansion phase it twice exceeds the day-to-night global flux transfer rate. (2) Different types of substorms were revealed. About 1/3 of all substorms considered displayed very weak growth in the tail lobe magnetic field before the onset. For these events the plasma sheet transport was found to be in a balance with the day-to-night flux transfer, as in the SMC events. However, the lobe magnetic field value in these cases was as large as that in the substorms with a classic growth phase just before the onset (both values exceed the average level of the lobe field during the SMC). Also, in both groups similar configurational changes (magnetic field stretching and plasma sheet thinning) were observed before the substorm onset. (3) Superimposed epoch analysis showed that the plasma sheet during the late substorm recovery phase has the characteristics similar to those found during SMC events, the SMC could be a natural magnetospheric state following the substorm.

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“…As in PR96, the α(x) dependence is taken as sin 2 α = A 2 exp(Cx). According to the statistical study by Shukhtina et al (2004), the average C value is C = 0.0714. All formulas are presented in the geocentric solar magnetospheric (GSM) coordinate system.…”

Section: Introductionmentioning

confidence: 99%

In situ magnetotail magnetic flux calculation

Shukhtina

Gordeev

2015

Ann. Geophys.

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Abstract. We explore two new modifications of the magnetotail magnetic flux (F ) calculation algorithm based on the Petrinec and Russell (1996) (PR96) approach of the tail radius determination. Unlike in the PR96 model, the tail radius value is calculated at each time step based on simultaneous magnetotail and solar wind observations. Our former algorithm, described in Shukhtina et al. (2009), required that the "tail approximation" requirement were fulfilled, i.e., it could be applied only tailward x ∼ −15 R E . The new modifications take into account the approximate uniformity of the magnetic field of external sources in the near and middle tail. Tests, based on magnetohydrodynamics (MHD) simulations, show that this approach may be applied at smaller distances, up to x ∼ −3 R E . The tests also show that the algorithm fails during long periods of strong positive interplanetary magnetic field (IMF) B z . A new empirical formula has also been obtained for the tail radius at the terminator (at x = 0) which improves the calculations.

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Quantitative magnetotail characteristics of different magnetospheric states

Cited by 45 publications

References 46 publications

On the conditions preceding sudden magnetotail magnetic flux unloading

On the conditions preceding sudden magnetotail magnetic flux unloading

Average characteristics of the midtail plasma sheet in different dynamic regimes of the magnetosphere

In situ magnetotail magnetic flux calculation

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