The Crab Nebula Radio Pulsar: Is it Different?

奖项：AST-0607492PI：Timothy HankinsInstitution：新墨西哥州采矿与技术研究所TITLE：蟹状星云射电脉冲星：它不同吗？摘要人们认为，脉冲星磁层的射电辐射是由旋转系统中的等离子体电动力学决定的，在旋转系统中，磁场足够强，足以产生量子效应，感应电场足够强，足以加速对高洛伦兹因子的充电。然而，物理条件和发射机制细节的理论模型在很大程度上没有受到挑战，因为它们很难与传统的脉冲星观测进行测试。然而，由于模型对短时间尺度的预测存在分歧，PI一直在追求对蟹状星云脉冲星的高时间分辨率观测。为此目的开发的新的数据采集系统已经探测到了来自螃蟹主脉冲区和产生相干射电发射的基本实体的纳秒长射电爆发。这些“纳米快照”的时间和频率特性与强等离子体湍流模型一致。然而，随后对第二个发射区--脉间脉冲星的观测显示，时间和频率特征截然不同，这表明它们的物理条件完全不同，这是很难解释的。由于蟹状脉冲星的年龄较小，所以它不寻常，因此将对一小组(五颗)明亮的脉冲星进行类似的研究。这些脉冲星被选为代表其他脉冲星可能情况的范围，观测将揭示从螃蟹发出的辐射类型是否是一般脉冲星的典型。对于Crab本身，微秒时间尺度上的强度和偏振起伏，以及时间平均的偏振特征，将通过PI执行的额外理论建模与发射区的物理条件相联系。我们还将认真研究脉冲间发射的理论模型，以确定哪种现有模型可以解释这些观测结果。研究生和本科生将直接参与这项工作的所有方面--从构建和维护数据收集系统到开发用于建模和分析的数字代码。在实验室之外，这里使用的一些研究工具将用于当地课堂教学，并将科学成果纳入基于网络的教材(除了在专业文献中传播之外)。最先进的采集系统将作为这项工作的一部分加以改进，将在合作的基础上提供给射电天文学团体。由PIS开发的数据采集和控制软件直接适用于新墨西哥理工学院大气物理小组的闪电研究，并可用于该研究。

AWARD NO: AST-0607492PI: Timothy HankinsINSTITUTION: New Mexico Institute of Mining and TechnologyTITLE: The Crab Nebula Radio Pulsar: Is it Different?ABSTRACTIt is thought that the radio emissions from pulsar magnetospheres are ruled by plasmaelectrodynamics in a rotating system where the magnetic field is strong enough forquantum effects to matter and the induced electric field is strong enough to acceleratecharges to high Lorentz factors. Yet theoretical models of the physical conditions anddetails of the emission mechanism have gone largely unchallenged because of thedifficulty testing them against traditional pulsar observations. However, because modelsdiverge in their predictions for short timescales, the PIs have been pursuing high timeresolution observations of the Crab Nebula pulsar. New data acquisition systemsdeveloped for this purpose have detected nanosecond long radio bursts from the Crab'sMain Pulse region and the fundamental entities creating the coherent radio emission. Thetime and frequency characteristics of these "nanoshots" are consistent with a strongplasma turbulence model. However, subsequent observations of a second emitting region,the Interpulse, revealed dramatically different time and frequency signatures indicatingsubstantially different physical conditions which are difficult to explain.As the Crab pulsar is unusual because of its young age, a similar study of a small set(five) of bright pulsars will be undertaken. These pulsars have been chosen to representthe range of likely conditions in other pulsars and the observations will reveal whetherthe type of emission from the Crab is typical of the general pulsar population. For theCrab itself, intensity and polarization fluctuations on microsecond timescales, as well astime averaged polarization signatures, will be connected to the physical conditions in theemission region by additional theoretical modeling performed by the PIs. Theoreticalmodels of the Interpulse emission will also be critically studied to determine which, ifany, existing model can explain these observations.Graduate and undergraduate students will be directly involved in all aspects of this work- from constructing and maintaining the data collection systems to developing thenumerical codes for modeling and analysis. Beyond the laboratory, some of the researchtools used here will be made available for teaching in local classes and the scientificresults incorporated into web-based teaching materials (in addition to dissemination inthe professional literature). The state-of-the-art acquisition systems, which will beimproved as part of this work, will be made available to the radio astronomy communityon a collaborative basis. The data acquisition and control software developed by the PIsis directly applicable to, and available for use in lightning research by the AtmosphericPhysics group at New Mexico Tech.