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"Larson, D."
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Quantifying the Energy Budget in the Solar Wind from 13.3 to 100 Solar Radii
A variety of energy sources, ranging from dynamic processes, such as magnetic reconnection and waves, to quasi-steady terms, such as plasma pressure, may contribute to the acceleration of the solar wind. We utilize a combination of charged particle and magnetic field observations from the Parker Solar Probe (PSP) to attempt to quantify the steady-state contribution of the proton pressure, the electric potential, and the wave energy to the solar wind proton acceleration observed by PSP between 13.3 and ∼100 solar radii (R ☉). The proton pressure provides a natural kinematic driver of the outflow. The ambipolar electric potential acts to couple the electron pressure to the protons, providing another definite proton acceleration term. Fluctuations and waves, while inherently dynamic, can act as an additional effective steady-state pressure term. To analyze the contributions of these terms, we utilize radial binning of single-point PSP measurements, as well as repeated crossings of the same stream at different distances on individual PSP orbits (i.e., fast radial scans). In agreement with previous work, we find that the electric potential contains sufficient energy to fully explain the acceleration of the slower wind streams. On the other hand, we find that the wave pressure plays an increasingly important role in the faster wind streams. The combination of these terms can explain the continuing acceleration of both slow and fast wind streams beyond 13.3 R ☉.
Journal Article
التدريب العلمي للأطفال : دليلك الإرشادي التفصيلي لتربية أطفال عباقرة وموهوبين
كتاب التدريب العلمي للأطفال من تأليف كريستيان لارسون هو دليل شامل يهدف إلى مساعدة الآباء في تربية أطفال موهوبين وعباقرة. يتناول الكتاب موضوعات حيوية، بدءا من كيفية تشجيع الأطفال على تحقيق أهدافهم منذ الصغر، وصولا إلى أهمية التعامل مع الأطفال بأسلوب إيجابي يعزز من ثقتهم بأنفسهم ويحفز طاقاتهم الكامنة. يقدم لارسون نصائح قيمة حول كيفية تنمية القدرات التخيلية للأطفال وتوجيهها بشكل صحيح، وكذلك أهمية الإجابة على تساؤلاتهم بطرق منطقية ووافية، مما يسهم في تكوين عقلية نقدية ومبدعة. هذا الكتاب ليس مجرد مجموعة من النصائح، بل هو خارطة طريق تمكن الآباء من اكتشاف أفضل الطرق لرعاية أطفالهم وتنميتهم. من خلال الفصول المتعددة، سيتعلم الآباء كيفية خلق بيئة محفزة تشجع الأطفال على التفكير المستقل والإبداع. لا شك أن هذا الكتاب يعد من أهم الكتب التي يجب أن تكون في مكتبة كل والد ووالدة في العصر الحالي. إن تطبيق الأسس العلمية والنفسية التي يطرحها كريستيان لارسون سيحدث فارقا كبيرا في حياة أطفالكم، وسيجعلهم مهيئين لتحقيق نجاحات باهرة في المستقبل.
Book
Interchange reconnection as the source of the fast solar wind within coronal holes
The fast solar wind that fills the heliosphere originates from deep within regions of open magnetic field on the Sun called ‘coronal holes’. The energy source responsible for accelerating the plasma is widely debated; however, there is evidence that it is ultimately magnetic in nature, with candidate mechanisms including wave heating
1
,
2
and interchange reconnection
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–
5
. The coronal magnetic field near the solar surface is structured on scales associated with ‘supergranulation’ convection cells, whereby descending flows create intense fields. The energy density in these ‘network’ magnetic field bundles is a candidate energy source for the wind. Here we report measurements of fast solar wind streams from the Parker Solar Probe (PSP) spacecraft
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that provide strong evidence for the interchange reconnection mechanism. We show that the supergranulation structure at the coronal base remains imprinted in the near-Sun solar wind, resulting in asymmetric patches of magnetic ‘switchbacks’
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,
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and bursty wind streams with power-law-like energetic ion spectra to beyond 100 keV. Computer simulations of interchange reconnection support key features of the observations, including the ion spectra. Important characteristics of interchange reconnection in the low corona are inferred from the data, including that the reconnection is collisionless and that the energy release rate is sufficient to power the fast wind. In this scenario, magnetic reconnection is continuous and the wind is driven by both the resulting plasma pressure and the radial Alfvénic flow bursts.
Measurements of fast solar wind streams from the Parker Solar Probe spacecraft provide strong evidence for the interchange reconnection mechanism being responsible for accelerating the fast solar wind.
Journal Article
Sub-Alfvénic Solar Wind Observed by the Parker Solar Probe: Characterization of Turbulence, Anisotropy, Intermittency, and Switchback
In the lower solar coronal regions where the magnetic field is dominant, the Alfvén speed is much higher than the wind speed. In contrast, the near-Earth solar wind is strongly super-Alfvénic, i.e., the wind speed greatly exceeds the Alfvén speed. The transition between these regimes is classically described as the “Alfvén point” but may in fact occur in a distributed Alfvén critical region. NASA’s Parker Solar Probe (PSP) mission has entered this region, as it follows a series of orbits that gradually approach more closely to the Sun. During its 8th and 9th solar encounters, at a distance of ≈16 R ⊙ from the Sun, PSP sampled four extended periods in which the solar wind speed was measured to be smaller than the local Alfvén speed. These are the first in situ detections of sub-Alfvénic solar wind in the inner heliosphere by PSP. Here we explore properties of these samples of sub-Alfvénic solar wind, which may provide important previews of the physical processes operating at lower altitude. Specifically, we characterize the turbulence, anisotropy, intermittency, and directional switchback properties of these sub-Alfvénic winds and contrast these with the neighboring super-Alfvénic periods.
Journal Article
Strong Perpendicular Velocity-space Diffusion in Proton Beams Observed by Parker Solar Probe
The SWEAP instrument suite on Parker Solar Probe (PSP) has detected numerous proton beams associated with coherent, circularly polarized, ion-scale waves observed by PSP’s FIELDS instrument suite. Measurements during PSP Encounters 4−8 revealed pronounced complex shapes in the proton velocity distribution functions (VDFs), in which the tip of the beam undergoes strong perpendicular diffusion, resulting in VDF level contours that resemble a “hammerhead.” We refer to these proton beams, with their attendant “hammerhead” features, as the ion strahl. We present an example of these observations occurring simultaneously with a 7 hr ion-scale wave storm and show results from a preliminary attempt at quantifying the occurrence of ion-strahl broadening through three-component ion VDF fitting. We also provide a possible explanation of the ion perpendicular scattering based on quasilinear theory and the resonant scattering of beam ions by parallel-propagating, right circularly polarized, fast magnetosonic/whistler waves.
Journal Article
The Eagle has landed : 50 years of lunar science fiction
\"In celebration of the 50th anniversary of the Apollo 11 landing, the endlessly-mysterious moon is explored in this reprint short science fiction anthology from award-winning editor and anthologist Neil Clarke ... On July 20, 1969, mankind made what had only years earlier seemed like an impossible leap forward: when Apollo 11 became the first manned mission to land on the moon, and Neil Armstrong the first person to step foot on the lunar surface. While there have only been a handful of new missions since, the fascination with our planet's satellite continues, and generations of writers and artists have imagined the endless possibilities of lunar life. From adventures in the vast gulf of space between the earth and the moon, to journeys across the light face to the dark side, to the establishment of permanent residences on its surface, science fiction has for decades given readers bold and forward-thinking ideas about our nearest interstellar neighbor and what it might mean to humankind, both now and in our future. [This book] collects the best stories written in the fifty years since mankind first stepped foot on the lunar surface, serving as a shining reminder that the moon is and always has been our most visible and constant example of all the infinite possibility of the wider universe\"-- Provided by publisher.
BOOK
N-glycosylation of monoclonal light chains on routine MASS-FIX testing is a risk factor for MGUS progression
Our group previously demonstrated that M-protein light chain (LC) glycosylation can be detected on routine MASS-FIX testing. Glycosylation is increased in patients with immunoglobulin LC amyloidosis (AL) and rarely changes over the course of a patient’s lifetime. To determine the rates of progression to AL and other plasma cell disorders (PCDs), we used residual serum samples from the Olmsted monoclonal gammopathy of undetermined significance (MGUS) screening cohort. Four-hundred and fourteen patients with known MGUS were tested by MASS-FIX, and 25 (6%) were found to have glycosylated LCs. With a median follow-up of surviving patients of 22.2 years, the 20-year progression rates to a malignant PCD were 67% (95% CI 29%, 84%) and 13% (95% CI 9%, 18%) for patients with and without glycosylated LCs, respectively. The risk of progression was independent of Mayo MGUS risk score. The respective rates of progression to AL at 20 years were 21% (95% CI 0.0%, 38%) and 3% (95% CI 0.6%, 5.5%). In summary, monoclonal LC glycosylation is a potent risk factor for progression to AL, myeloma, and other PCDs, an observation which could lead to earlier diagnoses and potentially reduced morbidity and mortality.
Journal Article