Anti-sunward high-speed jets in the subsolar magnetosheath

Using 2008–2011 data from the five Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft in Earth's subsolar magnetosheath, we study high-speed jets identified as intervals when the anti-sunward component of the dynamic pressure in the subsolar magnetosheath exceeds half of its upstream solar wind value. Based on our comprehensive data set of 2859 high-speed jets, we obtain the following statistical results on jet properties and favorable conditions: high-speed jets occur predominantly downstream of the quasi-parallel bow shock, i.e., when interplanetary magnetic field cone angles are low. Apart from that, jet occurrence is only very weakly dependent (if at all) on other upstream conditions or solar wind variability. Typical durations and recurrence times of high-speed jets are on the order of tens of seconds and a few minutes, respectively. Relative to the ambient magnetosheath, high-speed jets exhibit higher speed, density and magnetic field intensity, but lower and more isotropic temperatures. They are almost always super-Alfvénic, often even super-magnetosonic, and typically feature 6.5 times as much dynamic pressure and twice as much total pressure in anti-sunward direction as the surrounding plasma does. Consequently, they are likely to have significant effects on the magnetosphere and ionosphere if they impinge on the magnetopause

Benefits realisation in post-implementation development of ERP systems

Abstract. Complex applications, like Enterprise Resource Planning (ERP) systems, that significantly influence organisational performance and business strategies, are the most challenging in terms of identifying and managing expected benefits. ERP systems can generate benefits from variety of underlying factors, but systems do not provide benefits on their own. In this, formal benefits realisation practices can be highly effective. The existing ERP research has largely focused on ERP implementations leaving the post-implementation phase to lesser attention. Nevertheless, the work does not end there, but continues with post-implementation activities which aim to ensure also the future benefits from the ERP systems. Motivated by the insufficient research regarding benefits realisation in post-implementation development of ERP system, this study aimed to identify how organisations manage benefits realisation in post-implementation phase of ERP systems, what challenges they might face and how the benefits realisation is ensured. It was also the purpose to find out what tools or methods organisation use in this. This study was a revelatory embedded single-case study with positivist approach. Qualitative data was collected from interviews and documents supported by data from the ERP system. This study is revelatory, because access was gained to the Case organisation’s data to study phenomenon inaccessible previously. The data was analysed inductively allowing patterns and concepts to arise and the findings were evaluated through theoretical lenses. The aim of all the chosen methods was to get rich, in depth understanding of the phenomenon. It is argued that this study has created in-depth understanding of circumstances and challenges of benefits realisation in post-implementation development of ERP system providing window to phenomenon largely unstudied before. It was identified that old and evolved business processes, which are further complicated by workarounds, can be unfamiliar to Information Technology (IT) and business managers responsible of ERP development making it largely difficult to identify all benefits. Moreover, when subsidiaries are unable to identify new benefits on their own and the benefits further vary from one subsidiary to another, the complexity increases further. These unique characteristics, that surround ERP post-implementation development, require modified approach to benefits realisation practices. This is the main contribution of this study

Ion temperature anisotropy across a magnetotail reconnection jet

A significant fraction of the energy released by magnetotail reconnection appears to go into ion heating, but this heating is generally anisotropic. We examine ARTEMIS dual-spacecraft observations of a long-duration magnetotail exhaust generated by anti-parallel reconnection in conjunction with Particle-In-Cell simulations, showing spatial variations in the anisotropy across the outflow far (> 100di) downstream of the X-line. A consistent pattern is found in both the spacecraft data and the simulations: Whilst the total temperature across the exhaust is rather constant, near the boundaries Ti,|| dominates. The plasma is well-above the firehose threshold within patchy spatial regions at |BX| ∈ [0.1, 0.5]B0, suggesting that the drive for the instability is strong and the instability is too weak to relax the anisotropy. At the mid-plane (|BX|0.1 B0), Ti,⊥ > Ti,|| and ions undergo Speiser-like motion despite the large distance from the X-line

Detection of small-scale folds at a solar wind reconnection exhaust

Observations of reconnection in the solar wind over the last few years appear to indicate that the majority of large-scale reconnecting current sheets are roughly planar, and that reconnection itself is quasi-steady. Most studies of solar wind exhausts have used spacecraft with large separations and relatively low time cadence ion measurements. Here we present multipoint Cluster observations of a reconnection exhaust and the associated current sheet at ACE and Wind, enabling it to be studied on multiple length scales and at high time resolution. While analysis shows that on large scales the current sheet is planar, detailed measurements using the four closely spaced Cluster spacecraft show that the trailing edge of the reconnection jet is nonplanar with folds orthogonal to the reconnection plane, with length scales of approximately 230 ion inertial lengths. Our findings thus suggest that while solar wind current sheets undergoing reconnection may be planar on large scales, they may also exhibit complex smaller-scale structure. Such structure is difficult to observe and has rarely been detected because exhausts are rapidly convected past the spacecraft in a single cut; there is therefore a limited set of spacecraft trajectories through the exhaust which would allow the nonplanar features to be intercepted. We consider how such nonplanar reconnection current sheets can form and the processes which may have generated the 3-D structure that was observed

Museo tiedon jakajana:tapaustutkimus Kansallismuseon Kotiinpaluu-näyttelystä

Tiivistelmä. Informaatiotutkimuksen kandidaatintutkielmani käsittelee tapaustutkimuksen kautta museota tiedon jakajana. Kansallismuseon Kotiinpaluu-näyttely järjestettiin vuosina 2021–2022 saamelaiskokoelman palauttamiseen liittyen, koska saamelaismuseo Siida sai kokoelman haltuunsa. Tutkimusmenetelmänä oli havainnointi tapaustutkimuksessa. Tutkimuksen taustaa ovat tiedon jakaminen ja levittäminen sekä museot oppimisen paikkana. Lisäksi käsittelen digitalisaatiota museoyhteydessä. Käsittelen repatriaatiota laajemminkin maailmassa sekä eri menetelmiä sen toteuttamisessa. Repatriaatio on museokentällä ajankohtainen aihe ja uusia päätöksiä esineiden palauttamisesta tulee mediassa julki jatkuvasti. Digitalisaatiota on hyödynnetty repatriaatiossa, koska fyysisten esineiden palauttaminen ei aina ole mahdollista. Digitalisaatio mahdollistaa myös tiedon levittämisen ja vaihtamisen

Supermagnetosonic jets behind a collisionless quasi-parallel shock

The downstream region of a collisionless quasi-parallel shock is structured containing bulk flows with high kinetic energy density from a previously unidentified source. We present Cluster multi-spacecraft measurements of this type of supermagnetosonic jet as well as of a weak secondary shock front within the sheath, that allow us to propose the following generation mechanism for the jets: The local curvature variations inherent to quasi-parallel shocks can create fast, deflected jets accompanied by density variations in the downstream region. If the speed of the jet is super(magneto)sonic in the reference frame of the obstacle, a second shock front forms in the sheath closer to the obstacle. Our results can be applied to collisionless quasi-parallel shocks in many plasma environments.Comment: accepted to Phys. Rev. Lett. (Nov 5, 2009