609 research outputs found

    Effects of solar wind density on auroral electrojets and brightness under influence of substorms

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    Using the auroral electrojet indices and Polar Ultraviolet Imager auroral images, we examined two fortuitous events during which the solar wind density had clear enhancements while the other solar wind parameters were relatively constant. Two electrojet enhancements were found in each event. The first electrojet enhancement was likely to be related to a substorm in which an auroral bulge appeared at premidnight. The second electrojet enhancement was driven by the density enhancement in the solar wind. The auroral oval became wider in latitude and the auroral distribution became dispersed after the density enhancement arrived at the Earth. The total auroral power integrated over the entire nightside region from 50 to 80° MLAT, however, did not increase significantly in response to the density enhancement. Our interpretation is that the substorm that occurred prior to the solar wind density enhancement had drained out a significant portion of the stored energy in the magnetotail; therefore, less precipitation energy was deposited into the auroral ionosphere by the density enhancement

    Climate change and the duties of the disadvantaged: reply to Caney

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    Discussions of where the costs of climate change adaptation and mitigation should fall often focus on the ‘polluter pays principle’ or the ‘ability to pay principle’. Simon Caney has recently defended a ‘hybrid view’, which includes versions of both of these principles. This article argues that Caney’s view succeeds in overcoming several shortfalls of both principles, but is nevertheless subject to three important objections: first, it does not distinguish between those emissions which are hard to avoid and those which are easy to avoid; second, its only partial reference to all-things-considered justice means it cannot provide a full account even of climate justice; and third, it assigns to the poor very limited duties to meet climate change costs, even where they have created those costs, which may incentivise them to increase emissions. An alternative pluralistic account which avoids these objections is presented

    Pressure balance at the magnetopause: Experimental studies

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    The pressure balance at the magnetopause is formed by magnetic field and plasma in the magnetosheath, on one side, and inside the magnetosphere, on the other side. In the approach of dipole earth's magnetic field configuration and gas-dynamics solar wind flowing around the magnetosphere, the pressure balance predicts that the magnetopause distance R depends on solar wind dynamic pressure Pd as a power low R ~ Pd^alpha, where the exponent alpha=-1/6. In the real magnetosphere the magnetic filed is contributed by additional sources: Chapman-Ferraro current system, field-aligned currents, tail current, and storm-time ring current. Net contribution of those sources depends on particular magnetospheric region and varies with solar wind conditions and geomagnetic activity. As a result, the parameters of pressure balance, including power index alpha, depend on both the local position at the magnetopause and geomagnetic activity. In addition, the pressure balance can be affected by a non-linear transfer of the solar wind energy to the magnetosheath, especially for quasi-radial regime of the subsolar bow shock formation proper for the interplanetary magnetic field vector aligned with the solar wind plasma flow.Comment: 8 pages, 2 figure

    Extreme geomagnetic disturbances due to shocks within CMEs

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    We report on features of solar wind-magnetosphere coupling elicited by shocks propagating through coronal mass ejections (CMEs) by analyzing the intense geomagnetic storm of 6 August 1998. During this event, the dynamic pressure enhancement at the shock combined with a simultaneous increase in the southward component of the magnetic field resulted in a large earthward retreat of Earth\u27s magnetopause, which remained close to geosynchronous orbit for more than 4 h. This occurred despite the fact that both shock and CME were weak and relatively slow. Another similar example of a weak shock inside a slow CME resulting in an intense geomagnetic storm is the 30 September 2012 event, which strongly depleted the outer radiation belt. We discuss the potential of shocks inside CMEs to cause large geomagnetic effects at Earth, including magnetopause shadowing

    Capabilitarian Sufficiency: Capabilities and Social Justice

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    This paper suggests an account of sufficientarianism—that is, that justice is fulfilled when everyone has enough—laid out within a general framework of the capability approach. In doing so, it seeks to show that sufficiency is especially plausible as an ideal of social justice when constructed around key capabilitarian insights such as freedom, pluralism, and attention to empirical interconnections between central capabilities. Correspondingly, we elaborate on how a framework for evaluating social justice would look when constructed in this way and give reasons for why capabilitarians should embrace sufficientarianism. We do this by elaborating on how capabilitarian values underpin sufficiency. On this basis, we identify three categories of central capabilities; those related to biological and physical needs, those to fundamental interests of a human agent, and those to fundamental interests of a social being. In each category, we argue, achieving sufficiency requires different distributional patterns depending on how the capabilities themselves work and interrelate. This argument adds a new dimension to the way capabilitarians think about social justice and changes how we should target instances of social justice from social-political viewpoint

    Intergenerational justice: a framework for addressing intellectual property rights and climate change

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    At first blush, one may wonder what contribution normative theory can make to what seems to be such a technical/political issue as the role of intellectual property rights (IPRs) in the global climate change regime. There are two answers to this. Firstly, as eloquently put by Joe Bowersox,“... normative theory… can be a powerful diagnostic tool for evaluating public policy; it can act as an altimeter, if you will, that checks the thinness of the theoretical air surrounding a particular policy mountain or molehill, telling us whether there is enough oxygen present to support political life. Sometimes theory may even suggest that we try an alternative, less precipitous policy pass by which to cross to the other side.” Conceptions about justice - can provide a valuable framework in terms of ensuring that policy prescriptions are well directed, particularly given that economic policy discourse can bury ethical assumptions. This broader picture, can provide a valuable point of reference in the highly technical debates relating to intellectual property rights and climate change. A second reason for turning to normative theory is the reality that environmental treaties will not be agreed to without at least overlapping conceptions of fairness. This provides a practical motivation for interrogating more deeply justice discourses involved in the climate change negotiations. To the extent that the current global climate regime is inadequate, shared understandings of justice are a crucial precondition for reforming and making more effective the current climate change regime
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