Substorms during different storm phases

Partamies, Noora; Juusola, Liisa; Tanskanen, Eija; Kauristie, Kirsti; Weygand, J. M.; Ogawa, Y.

doi:10.5194/angeo-29-2031-2011

Cited by 18 publications

(19 citation statements)

References 39 publications

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“…Considering the median index values, the substorm recovery phase is typically as intense as the expansion phase, and thus plays an important role in dissipating the storm energy, even when the role of the expansion phase is emphasised during storm-times. This is in agreement with the results of an event study by Partamies et al (2011). Yet, there are a lot of unanswered questions about substorm recovery phase processes.…”

Section: Discussionsupporting

confidence: 91%

“…In this light, it is not surprising that the case studies found in the literature are so different from each other. In fact, the substorm phase lifetimes during different storm phases reported by Partamies et al (2011) are much longer than the statistical values found in this study. The largest range of lifetimes is covered by the durations of substorm recovery phases, from 11 min of the single-cycle substorm recoveries during the storm main phases to the 37 min of the multi-cycle substorm recoveries during the storm recovery phases (Table 7).…”

Section: Discussioncontrasting

confidence: 73%

“…Furthermore, our substorm phase identification routine has a median AL value (−50 nT) as a threshold for the end of a substorm instead of threshold values that are related to the minimum AL of each event. For instance, recovery of 80 % of the minimum value has determined the end of substorm events analysed by Partamies et al (2011);Tanskanen (2009). This makes the selection criteria used in this paper more sensitive for new substorm expansion phases in the middle of recovery phases.…”

Section: Discussionmentioning

confidence: 99%

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Statistical properties of substorms during different storm and solar cycle phases

et al. 2013

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Abstract. Substorm properties during different storm phases have been studied using an automated recognition of substorm and storm phases in the auroral electrojet (AL) and ring current (Dst) index data from 1995–2009. The large number of events (about 500 storms and 15 000 substorms) provides statistically reliable distributions, average behaviour and long time series of simple parameters, such as durations and intensities. The phases of storms and substorms have been examined independently. Substorm phases have been further combined to single and multi-cycle events. The former consist of one growth, one expansion and one recovery phase, while the latter include multiple expansion and recovery phases after one growth phase. Our findings show that most substorms take place during non-storm times, and substorms during storm initial phases resemble isolated non-storm time substorms. Both during storm initial phases and non-storm times, the substorm growth phases may last longer than the other substorm phases. Substorm recovery phase is typically the longest phase but its duration also varies most. The longest substorm recovery phase duration was observed during multi-cycle substorms. The longest substorm expansion and storm main phases were found during the years close to the solar maximum. The shortest substorm events (the shortest phase durations) are the single-cycle substorms. The period of expansion onsets during multi-cycle substorms varied hugely for events with a small number of expansion phases. For events with a larger number of expansions, a clearer periodicity of about one hour (median value) was suggested.

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Section: Discussionsupporting

confidence: 91%

Section: Discussioncontrasting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

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Statistical properties of substorms during different storm and solar cycle phases

et al. 2013

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“…Geomagnetic storms and substorms are important space weather phenomena and an intensely active space weather research topic. Many investigators have studied geomagnetic storms and substorms (e.g., Akasofu and Chapman, 1963;Lakhina et al, 2006;Russell et al, 1974;Partamies et al, 2011). It is well known that substorms can occur during super storms and intense storms, or even independently of storms (Hajra et al, 2016;Partamies et al, 2013;Tsurutani et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Statistical study on interplanetary drivers behind intense geomagnetic storms and substorms

Tian

Chang

Sun

et al. 2019

Earth and Planetary Physics

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Geomagnetic storms and substorms play a central role in both the daily life of mankind and in academic space physics. The profiles of storms, especially their initial phase morphology and the intensity of their substorms under different interplanetary conditions, have usually been ignored in previous studies. In this study, 97 intense geomagnetic storms (Dstmin ≤ –100 nT) between 1998 and 2018 were studied statistically using the double superposed epoch analysis (DSEA) and normalized superposed epoch analysis (NSEA) methods. These storms are categorized into two types according to different interplanetary magnetic field (IMF) Bz orientations: geomagnetic storms whose IMF is northward, both upstream and downstream relative to the interplanetary shock, and geomagnetic storms whose upstream and downstream IMF is consistently southward. We further divide these two types into two subsets, by different geomagnetic storm profiles: Type I/Type II — one/two‐step geomagnetic storms with northward IMF both upstream and downstream of the interplanetary shock; Type III/TypeIV — one/two‐step geomagnetic storms with southward IMF both upstream and downstream of the interplanetary shock. The results show that: (1) geomagnetic storms with northward IMF both upstream and downstream of the interplanetary shock have a clear initial phase; geomagnetic storms with southward IMF in both upstream and downstream of the interplanetary shock do not; (2) the IMF is an important controlling factor in affecting the intensity characteristics of substorms. When Bz is positive before and after the interplanetary shock arrival, the Auroral Electrojet (AE) index changes gently during the initial phase of geomagnetic storms, the median value of AE index is maintained at 500–1000 nT; (3) whenBz is negative before and after the interplanetary shock arrival, the AE index rises rapidly and reaches its maxmum value about one hour after storm sudden commencements (SSC), although the time is scaled between reference points and the maximum value of AE is usually greater than 1,000 nT, representing intense substorms; (4) for most cases, the Dst0 usually reaches its minimum at least one hour after Bz. These results are useful in improving contemporary space weather models, especially for those that address geomagnetic storms and substorms.

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“…Many researchers studied this problem using both satellite data and ground-based data (IMAGE magnetometers data, AL, AU indexes, data of auroras) (e.g. Tsurutani et al 2004;Milan et al, 2008Milan et al, , 2009Partamies et al, 2011;Despirak et al, 2009Despirak et al, , 2011. It is known that as a result from storm investigations, the various phases of the storm were defined.…”

Section: Introductionmentioning

confidence: 99%

Substorm observations by THEMIS D and ground-based observations by MAIN camera system in Apatity - a case study

Guineva¹,

Despirak²,

Werner³

2018

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In this work we studied the development of a substorm during the geomagnetic storm on 23 December 2014 using data of THEMIS D (THD) satellite, ground based magnetic field measurements and auroras observations by the Multiscale Aurora Imaging Network (MAIN) in Apatity. Solar wind and interplanetary magnetic field parameters were taken from the OMNI data base. THD was located at ~ 7Re from 18:30 to 19:30 UT in the time interval 23-24 December 2014 and the projection of its orbit crossed Kola Peninsula in this time. A substorm was observed over Apatity from 19:19:50 UT on 24 December 2014. A comparative analysis between ground based and satellite data was carried out. High energy electrons (1-10 keV) injections and reduction of the less energetic electrons flux (~100 eV) were observed during the substorm. Particles density reduction was found at the time about the auroras intensifications. Plasma fast flows were identified during the consecutive auroras intensifications. The time delay between the beginning of the different parameters disturbances registered by THD and the ground based observed ones is about 1.0 ÷ 1.5 min.

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Substorms during different storm phases

Cited by 18 publications

References 39 publications

Statistical properties of substorms during different storm and solar cycle phases

Statistical properties of substorms during different storm and solar cycle phases

Statistical study on interplanetary drivers behind intense geomagnetic storms and substorms

Substorm observations by THEMIS D and ground-based observations by MAIN camera system in Apatity - a case study

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