Interplanetary shock parameters during solar activity maximum (2000) and minimum (1995-1996)

Echer, E.; González, W. D.; Vieira, L. E. A.; Lago, A. Dal; Guarnieri, F. L.; Prestes, A.; González, Alicia; Schuch, Nelson Jorge

doi:10.1590/s0103-97332003000100010

Cited by 40 publications

(57 citation statements)

References 21 publications

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“…Shock analysis using the Rankine-Hugoniot conditions was applied to the interplanetary shocks (see Echer et al 2003Echer et al , 2010. Figure 9 shows the magnetosonic Mach number distribution calculated for the FS and RS shocks.…”

Section: Resultsmentioning

confidence: 99%

Solar wind effects on Jupiter non-Io DAM emissions during Ulysses distant encounter (2003–2004)

Echer

Zarka

González

et al. 2010

A&A

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Aims. We analyze solar wind data from the Ulysses spacecraft during the distant Jupiter encounter from 2003 November to 2004 March as well as Nançay decametric (DAM) radio observations non-controlled by Io. Methods. The Ulysses solar wind data are balistically propagated towards Jupiter and are correlated with Nançay non-Io DAM emissions. Results. It is found that the average solar wind dynamic pressure around the time of DAM emissions is 1.7 times higher than its average value during the Ulysses encounter. The occurrence of fast forward (FS) and reverse (RS) interplanetary shocks and heliospheric current sheet crossings (HCS) is correlated with the occurrence of non-Io DAM emissions. We note an enhanced probability of occurrence of non-Io DAM emissions after the expected arrival of FS, RS and HCS at Jupiter. However, about half emissions (54%) did not seem to be associated with these interplanetary structures. We also note that the average duration and power of non-Io DAM emissions are enhanced during periods associated with those interplanetary structures. Conclusions. From the results obtained in this work it seems that non-Io DAM emissions occur during intervals of enhanced solar wind dynamic pressure. Yet, there is no direct correlation between the non-Io DAM emissions duration or power versus the solar wind pressure values and the interplanetary shock Mach number.

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Section: Resultsmentioning

confidence: 99%

Solar wind effects on Jupiter non-Io DAM emissions during Ulysses distant encounter (2003–2004)

Echer

Zarka

González

et al. 2010

A&A

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“…The variations in solar wind parameters across the shocks were calculated using 20-min averaged data upstream (u) and downstream (d) of the shock. (Echer et al, 2003). The change in the solar wind speed across the shock exceeded 100 km/s −1 for all of the other events except for 25 July 2002.…”

Section: Interplanetary Shocksmentioning

confidence: 88%

Cluster observations of sudden impulses in the magnetotail caused by interplanetary shocks and pressure increases

et al. 2005

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Abstract. Sudden impulses (SI) in the tail lobe magnetic field associated with solar wind pressure enhancements are investigated using measurements from Cluster. The magnetic field components during the SIs change in a manner consistent with the assumption that an antisunward moving lateral pressure enhancement compresses the magnetotail axisymmetrically. We found that the maximum variance SI unit vectors were nearly aligned with the associated interplanetary shock normals. For two of the tail lobe SI events during which Cluster was located close to the tail boundary, Cluster observed the inward moving magnetopause. During both events, the spacecraft location changed from the lobe to the magnetospheric boundary layer. During the event on 6 November 2001 the magnetopause was compressed past Cluster. We applied the 2-D Cartesian model developed by Collier et al. (1998) in which a vacuum uniform tail lobe magnetic field is compressed by a step-like pressure increase. The model underestimates the compression of the magnetic field, but it fits the magnetic field maximum variance component well. For events for which we could determine the shock normal orientation, the differences between the observed and calculated shock propagation times from the location of WIND/Geotail to the location of Cluster were small. The propagation speeds of the SIs between the Cluster spacecraft were comparable to the solar wind speed. Our results suggest that the observed tail lobe SIs are due to lateral increases in solar wind dynamic pressure outside the magnetotail boundary.

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“…They occur when the relative difference between a fast solar wind stream (such as an interplanetary coronal mass ejection -ICME) and the slow, background solar wind stream is higher than the solar wind magnetohydrodynamics (MHD) characteristic speed -magnetosonic (Burgess, 1995;Echer et al, 2003). When the disturbance has a larger velocity than the fast mode MHD wave, a fast shock can be formed.…”

Section: Introductionmentioning

confidence: 99%

“…The plasma and magnetic field profiles through these different types of shocks are shown in Echer et al (2003). The main difference is that, for a forward shock, all observed parameters (density, velocity, temperature, magnetic field magnitude) show a positive jump across the shock, while for a reverse shock the magnetic field, density and temperature/pressures shows a negative jump.…”

Section: Introductionmentioning

confidence: 99%

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Positive and negative sudden impulses caused by fast forward and reverse interplanetary shocks

Andrioli¹,

Echer²,

Savian³

et al. 2007

Rev. Bras. Geof.

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ABSTRACT. Fast forward interplanetary shocks (FFS) are characterized by positive jump in all interplanetary plasma parameters (solar wind speed, temperature and density) and interplanetary magnetic field. However the fast reverse interplanetary shocks (FRS) are characterized by negative jump in all mentioned parameters except solar wind speed. Observations show that FFS cause positive sudden impulses (SI) while FRS cause negative SI in the H-component of the geomagnetic field. In this work we investigate the SI caused by interplanetary shocks. We use the observed plasma parameters, upstream and downstream, to calculate the variation of dynamic pressure. We observe that the SI amplitude is larger for positive SI than for negative ones, as a consequence of the fact that FFS have larger dynamic pressure variations as compared to FRS.Keywords: Solar wind, interplanetary shock waves, sudden impulses, magnetosphere. RESUMO. Choques interplanetários do tipo frontal rápido (FFS) são caracterizados por uma descontinuidade súbita positiva em todos os parâmetros de plasmainterplanetário (velocidade, temperatura e densidade do vento solar) e campo magnético interplanetário. Os choques do tipo reverso rápido (FRS) possuem descontinuidade súbita negativa em todos os parâmetros exceto a velocidade do vento solar. Observa-se que os FFS causam impulsos súbitos (SI) positivos e os FRS causam SI negativos na componente H do campo magnético terrestre. Neste trabalho realizou-se um estudo destes impulsos súbitos, causados por choques interplanetários.Utilizaram-se os parâmetros de plasma, antes e depois do choque, para calcular a variação da pressão dinâmica. Observou-se que os SIs são maiores quando causados por FFS que quando formados por FRS, isto porque os FFS possuem maior variação na pressão dinâmica que os FRS. Palavras-chave:Vento solar, ondas de choque interplanetárias, impulsos súbitos, magnetosfera.

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Interplanetary shock parameters during solar activity maximum (2000) and minimum (1995-1996)

Cited by 40 publications

References 21 publications

Solar wind effects on Jupiter non-Io DAM emissions during Ulysses distant encounter (2003–2004)

Solar wind effects on Jupiter non-Io DAM emissions during Ulysses distant encounter (2003–2004)

Cluster observations of sudden impulses in the magnetotail caused by interplanetary shocks and pressure increases

Positive and negative sudden impulses caused by fast forward and reverse interplanetary shocks

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