Faint Glow Research Articles

The evolution of our understanding of coronal mass ejections

The unexpected observation of a sudden expulsion of mass through the solar corona in 1971 opened up a new field of interest in solar and stellar physics. The discovery came from a white-light coronagraph, which creates an artificial eclipse of the Sun, enabling the viewing of the faint glow from the corona. This observation was followed by many more observations and new missions. In the five decades since that discovery, there have been five generations of coronagraphs, each with improved performance, enabling continued understanding of the phenomena, which became known as Coronal Mass Ejection (CME) events. The conceptualization of the CME structure evolved from the elementary 2-dimensional loop to basically two fundamental types: a 3-dimensional magnetic flux rope and a non-magnetic eruption from pseudo-streamers. The former persists to 1 AU and beyond, whereas the latter dissipates by 15 R⊙. Historically, most of the studies have been devoted to understanding the CME large-scale structure and its associations, but this is changing. With the advent of the fourth and fifth coronagraph generations, more attention is being devoted to the their internal structure and initiation mechanisms. In this review, we describe the evolution of CME observations and their associations with other solar and heliospheric phenomena, with one of the more important correlations being its recognition as a driver of space-weather. We conclude with a brief overview of open questions and present some ideas for future observations.

Tales from the lab

Tales from the lab

Corona discharge of a vibrated insulating box with granular medium

Corona discharges are luminous signs of strong local electric fields allowing a continuous discharge into the surrounding atmosphere. They commonly occur at the ends of conductors at high voltage. Here we report the observation of a faint glow surrounding an insulating cm-sized box filled with mm-sized basalt beads. At an ambient pressure in the mbar range two light bands occur as soon as and only if the box is vibrated and only if it is filled with a granular medium. In addition, a glow also occurs at the inside of the box. We measured periodic electric fields at the outside of the box with spatial peaks at the positions of the light bands. The period correlates to the vibration frequency. These observations imply strong alternating fields beyond atmospheric breakdown, which are generated inside and also emerge at the outside of the insulating box. The observations can be explained by tribocharging and periodic displacement of charges between grains and the inside walls of the box.

Atmospheric Dust Causes Darkness to Fall Rapidly on Mars

Abstract On mission sol 783 (at Martian solar longitude (L S ) of 217°), Mars Science Laboratory's MastCam instrument imaged a faint glow, extending upwards from the horizon (Figure 1(a)). The images were acquired from 18:58 to 19:01 LTST, nearly an hour after sunset occurred at 18:05 LTST, providing an opportunity to examine illumination in the Martian sky around sunset. The radiance of the observed glow is small when compared to daytime sky brightness values, with an average value between 20 and 35 μW m−2 Sr−1, and appears brightest in the blue filter (the average B/R ratio is 1.25). The total flux at the time of the measurement was calculated to be 4.2 × 10−4 W m−2, nearly three orders of magnitude dimmer than what would be expected for an Earth-like Atmosphere. An observer on the surface of Mars would thus find twilight becoming deeper much more rapidly than on the Earth.

Application of Luminescent Microscopy in Analysis of Anatomic-diagnostic Signs of Fruits of Sea Buckthorn

Introduction. Sea buckthorn (Hippophae rhamnoides), the family Eleagnaceae – a promising source of biologically active substances, the traditional raw materials of which are fruits. The existing regulatory documentation (ND) lacks such an indicator of the authenticity and good quality of the fruit as «microscopy». Despite the available data on the anatomy and histology of the fruits of this type of medicinal plant material (MPM), the scientific literature does not describe the luminescence features of the tissues of sea buckthorn fruit. It is known that the luminescent features of tissues make it possible to identify the localization of biologically active structures, and also, in some cases, to conduct selective diagnosis of MPM.Aim. The aim of this work was to study the characteristics of the luminescence of the tissues of dried crushed fruits of sea buckthorn, and also to optimize the conditions for analysis.Materials and methods. The object of the study was the dried, crushed fruits of sea buckthorn of various species. The study of microdiagnostic signs was carried out according to the State Pharmacopoeia of the XIV RF GPA.1.5.3.0003.15 «Technique of microscopic and microchemical studies of medicinal plant materials and herbal medicines». A stereomicroscopic study was carried out on a Biomed-6 microscope. The luminescence of sea buckthorn fruit tissues was examined using a luminescent microscope of the Micromed-3 Lum brand.Results and discussion. The most pronounced yellow glow is observed for the tissue of the pulp and epidermis of the fetus, which is associated with the highest content of fatty oil in these structures. Groups of phenolic compounds contained along with oil give a greenish tint to objects, while condensed tannins give a brownish tint. The plates that make up the corymbose hairs do not exhibit bright luminescence; a weak glow is characteristic of the joints of the hair platelets. The walls of stellate hairs have a faint greenish glow. Fragments of the actual fruit («sac») are brownish in color, without their own luminescence, as well as the seed peel. The embryo has its own greenish luminescence due to the presence of both a fatty oil and a complex of storage substances.Conclusion. The luminescent analysis of sea buckthorn fruits was carried out for the first time. The choice of a method for preparing the studied MPM for microscopic examination is experimentally substantiated. The luminescent analysis revealed the peculiarities of the glow of the tissues of the fruits of sea buckthorn. The main microdiagnostic signs of crushed dried sea buckthorn fruits and their biometric characteristics are specified. The analysis of the obtained data will allow us to further develop the section «Microscopic signs» for inclusion in the PA project on MPM, widely cultivated and used by the domestic pharmaceutical industry for the production of herbal medicines.

Gastrointestinal Occurrence of a Glomus Tumor

Glomus tumors are benign subepithelial mesenchymal neoplasms generally found in the fingers. It is rare to find a glomus tumor in the gastrointestinal tract. This is a case of a gastric glomus tumor (GGT). It is important to understand the difference betwen a glomus tumor and a gastrointestinal stromal tumor (GIST), which is far more common. The patient is a 26 year old Caucasian female who, for the past one year, had been visiting the gastroenterology clinic with complaints of epigastric abdominal pain, constipation, diarrhea, and heartburn. She was a moderately built individual with no abnormal vitals or notable findings on physical examination. We decided to do an EGD, and a mass in the body of the stomach was discovered. CT abdomen revealed a high density nodular lesion. EUS showed a 2.5cm x 2.2cm submucosal mass with mixed echogenicity and cystic spaces, arising from the muscularis propria of the stomach wall. The biopsy was consistent with a neuroendocrine lesion. Neuroendocrine markers were negative. However, smooth muscle actin and vimentin were strongly immunoreactive. Serotonin levels were normal, and octreotide scan revealed a faint glow in the tumor. Surgery was consulted and laparoscopic partial gastrectomy was performed. Pathology of the wedge resection revealed a gastric glomus tumor 1.8cm in diameter with well-defined margins and no evidence of malignancy. Subepithelial tumors of the gastrointestinal tract include carcinoid tumors, lymphomas, glomus tumors, and GIST. GIST, being the most common, are thought to arise from the interstitial cells of Cajal of the autonomic nervous system of the intestine. Glomus tumors arise from the glomus body in the intramuscular layer, typically in the antrum of the stomach. Both appear on CT as well-circumscribed homogenous masses, and on EUS as hypoechoic masses. However, GGT can be distinguished from GIST based on immunohistochemisty. GIST is typically positive for c-kit (CD117), whereas GGT may test positive for smooth muscle actin, laminin, collagen type IV, desmin, and vimentin.2680_A Figure 1. MR Abdomen, showing a 2.2cm homogenously-enhancing subepithelial gastric antral wall mass.2680_B Figure 2. Microscopic examination, showing multiple blood vessels surrounded by round glomus cells.Even though EUS-FNA differentiates GTs from more aggressive gastric tumors with a 95.6% accuracy, surgery is still preferred. According to the National Comprehensive Cancer Network, if the GIST is >2cm it should be surgically resected. Even if there were any doubt between a GT or GIST, wedge resection is the therapeutic management of choice. This rare case taught us how to diagnose and treat a gastrointestinal glomus tumor.

Global Aurora on Mars During the September 2017 Space Weather Event

AbstractWe report the detection of bright aurora spanning Mars' nightside during the space weather event occurring in September 2017. The phenomenon was similar to diffuse aurora detected previously at Mars, but 25 times brighter and detectable over the entire visible nightside. The observations were made with the Imaging UltraViolet Spectrograph, a remote sensing instrument on the Mars Atmosphere and Volatile EvolutioN spacecraft orbiting Mars. Images show that the emission was brightest around the limb of the planet, with a fairly uniform faint glow against the disk itself. Spectra identified four molecular emissions associated with aurora, and limb scans show the emission originated from an altitude of ~60 km in the atmosphere. Both are consistent with very high energy particle precipitation. The auroral brightening peaked around 13 September, when the flux of solar energetic electrons and protons both peaked. During the declining phase of the event, faint but statistically significant auroral emissions briefly appeared against the disk of the planet in the form of narrow wisps and small patches. These features are approximately aligned with predicted open field lines in the region of strong crustal magnetic fields in Mars' southern hemisphere.

For Heliconius' eyes only.

Some colours are the visual equivalent of a scream; from ‘Eat me’, to ‘Don't eat me’, to ‘Come hither’, plants and animals constantly flaunt their talents or warn each other off with pageants of colour. Adriana Briscoe from the University of California, Irvine, USA, explains that other animals sometimes take advantage of the deterrent effect of warning signals and imitate the bright markings to avoid the unwanted attentions of predators. One family that takes advantage of this form of mimicry are the Eueides butterflies that mimic the distinctive yellow bars found on the wings of their toxic distant Heliconius butterfly relatives. However, when Briscoe analysed the yellow pigment in Eueides butterfly wings and other members of the extended family, she found that it was different from the 3-hydroxy-dl-kynurenine (3-OHK) pigment that Keith Brown had found in Heliconius wings, even though the warning markings were extraordinarily similar to our eyes. Why had the butterflies adopted different pigments when both produced a bright yellow warning hue?Knowing that many animals see a broader palette of colours than are visible to us, Briscoe wondered whether the warning bar on the wings of red postman butterflies – Heliconius erato petiverana, which are members of the Heliconius family – is visible under UV light and was impressed when she discovered that it is. As Heliconius butterflies have an additional light receptor that is sensitive to violet shades, she realised that their 3-OHK-pigmented bar would appear completely different from the yellow shade that we see on Eueides’ wings; ‘this “UV-yellow” is a butterfly form of human purple, which is a mixture of red and blue light’, explains Briscoe. Could the 3-OHK marking be sending coded messages for the eyes of Heliconius butterflies only?Printing out thousands of paper butterflies with the red postman's distinctive red and black pattern, Susan Finkbeiner added yellow Manila paper covered with a UV filter to produce the correct shade of yellow without the UV component, while she reproduced the true red postman yellow shade with synthetic 3-OHK. In addition, some of the models were painted with yellow UV-reflective paint while others were covered with a UV filter. Then, she tested the attractiveness of the paper imposters to red postman butterflies and hungry birds. Analysing the butterflies’ responses, Finkbeiner, Briscoe and Daniel Osorio were impressed that the red postman butterflies always preferred the fake butterflies with 3-OHK UV in their yellow bands; and when they monitored the butterflies for longer periods, the insects made amorous advances to the 3-OHK models, while they were not seduced by the plain yellow paint substitutes. However, when Finkbeiner posed all four paper models in the forest to find out whether predatory birds had a preference for one pigment over the other, the birds found all of the models equally delectable. In addition, Briscoe made the exciting discovery that the 3-OHK pigment was fluorescent, producing a faint green glow: ‘We thought that the fluorescence might be contributing to the colour signal the butterflies were responding to’, says Briscoe. However, when Dmitry Fishman calculated the strength of the fluorescent message, the fluorescence was too faint to be seen when the butterflies are active in daylight.Briscoe suspects that toxic Heliconius butterflies adopted the novel UV-reflective 3-OHK pigment, in preference to the yellow pigment used by Eueides and other members of their extended family, to avoid confusion. ‘They [Heliconius] have two problems to solve: avoiding predators like birds and finding appropriate mates’, says Briscoe. She suggests that Heliconius butterflies evolved 3-OHK because it resembles the ancestral yellow sufficiently for birds to learn to give butterflies with yellow warning bars a wide berth, while allowing members of the Heliconius family to distinguish their own species from distant relatives when seeking a mate.

Generic delimitation between Fragariocoptes and Sierraphytoptus (Acari: Eriophyoidea: Phytoptidae) and a supplementary description ofFragariocoptes gansuensis with remarks on searching for mummified eriophyoid mites in herbaria under UV light.

Generic concepts of Fragariocoptes Roivainen, 1951 and Sierraphytoptus Keifer, 1939 are discussed and the correct delimitation between these two genera is given. A supplementary description of Fragariocoptes gansuensis Wei, Chen & Luo, 2005 is included based on fresh specimens from Astrakhan, Russia and dried mummies found in old herbaria collected in 1919 from southern European Russia of the cinquefoil, Potentilla bifurca L. (Rosaceae) with pathological stem proliferation. The male of this species is described for the first time. The cuticle of eriophyoid mummies emitted a faint glow under UV light wavelength equal to 365 nm of a common UV Light-Emitting diode (LED) lamp showing that this characteristic could be useful for quickly detecting eriophyoids in old herbaria which would otherwise be almost indistinguishable against the background under the regular white light source of a stereomicroscope. This was only possible for plant material stored in appropriate conditions enabling the autofluorescent signal of the dried mite cuticle to remain strong enough for observation.

Europe should launch satellite to monitor faint glow of plants, panel says

Europe should launch satellite to monitor faint glow of plants, panel says

Cosmology: The oldest cosmic light.

The cosmic microwave background is a faint glow of light left over from the Big Bang. It fills the entire sky and records the Universe's early history. Two independent experts outline what we know about this ancient light, both theoretically and observationally.

Measuring the faint glow of the Earth's thin exosphere

There is no “edge of space,” no sharp demarcation where the Earth's atmosphere ends and outer space begins. Instead, there is the fuzzy, progressively thinning exosphere, a region filled mostly by neutral hydrogen atoms that stretches from an altitude of 500 kilometers to hundreds of thousands of kilometers above the Earth's surface. So far, the outer detectable limit of the exosphere is around 15.5 Earth radii—roughly half the distance between the Earth and the Moon.

Use of a Video Assistive Device in a University Course in Laboratory Science: A Case Study

Many countries, including Canada (Government of Ontario, 2005) and the United States (U.S. Government, 2004) have legislated the provision of assistive devices for persons with disabilities during their education and subsequent employment to enable them to contribute more fully to society. The complex visual requirements of the laboratory component of many university science courses require a collaboration between a student with low vision and a particular university science department to determine which devices are appropriate for each student. A number of articles have addressed this issue for students who are totally blind and use special hardware (see, for example, Carver, 1967; Parry, Brazier, & Fischbach, 1997; University of Nottingham, 2009; Windelborn, 1999) or software (such as Thompson, 2005). The assistive devices described in those articles allow limited access to certain kinds of experiments, usually in mechanics, but are not applicable in general. In contrast, this article addresses the use of modern video technology to allow a student with low vision to participate almost fully in a standard university science program that includes laboratory experiments. CASE STUDY A student with low vision (the first author) registered in the introductory course at Trent University in the fall of 2009. His Snellen visual acuity fluctuates significantly, with an average acuity of about 20/400. This low acuity presented obvious difficulties for him with the laboratory component of the course, for which he relied on his lab partner for the setup of the apparatus and the collection of data, although he was a full participant in the data analysis. The student then decided to major in Trent's program in chemical physics. Because the required labs have visual components, these components needed to be evaluated for accessibility. The available options were to (1) continue relying on sighted classmates as in his first-year course, (2) create a different physics degree program that did not require a laboratory component, or (3) work with the student to find assistive technology that would allow him to participate in a meaningful way in setting up equipment and recording data. The student and the department agreed that familiarity with laboratory equipment and the skill in recording data properly were desirable benefits ensuing from the laboratory component and that would be expected by an employer of a or chemistry graduate, so the third option were the best one if it was possible. Even if the student continued into theoretical areas, laboratory experience would assist him in relating theory to an experiment. Selection of the assistive device Without an assistive device, the student could see the outline of a power supply or a signal generator but could not tell them apart visually or see the gradations on the dials. He could not select the voltage, current, or resistance on a digital multimeter or its banana-plug holes in which to insert patch cords. He also could not see his hands well enough to insert the patch cords even if he could have seen the holes. Thus, he could not assemble equipment, view physical results, or read meters to take data. For example, in the classic e/m (electron charge-to-mass ratio) experiment, he could not see the circular path of an electron beam in a magnetic field as evidenced by the faint glow from the excited mercury vapor or the pins that fluoresce, when struck by the beam, that determine the radius of the beam. To participate fully in an undergraduate experiment, he was required to see well enough to do all of these tasks while having his hands free to manipulate the equipment. The assistive device described here satisfied all these requirements. The student chose the Acrobat Panel and Long Arm (Enhanced Vision Systems, United States) for assessment. The weight is 3.5 pounds (1.6 kilograms) for the camera, long arm, and clamp, and 8 ounces (0. …

Visualizing CH* chemiluminescence in sooting flames

This investigation presents and validates a method to visualize CH* chemiluminescence in a sooting non-premixed flame. Excited-state CH radicals (A2Δ→X2Π, denoted CH*), upon relaxing, emit a photon in the visible portion of the electromagnetic spectrum, giving what is seen as a faint blue glow. Optical methods, especially those that rely on passive emission, provide a simple and non-intrusive means to characterize combustion; however, in the presence of hot solid particles – particularly soot – chemiluminescent emission can be obscured by blackbody radiation. This paper describes an image post-processing technique where flame emission is imaged through multiple filters near the CH* emission band in order to infer and filter the contribution of continuum radiation from soot in the CH* band. This information is then used to produce a soot-free image of CH* chemiluminescence.

Italian all‐sky imager tracks auroral red arcs over Europe

During geomagnetic storms, stable auroral red (SAR) arcs reach down from polar latitudes, their faint glow stretching equatorward of the traditional auroral oval. Invisible to the naked eye, SAR arcs are an upper atmospheric occurrence produced by the emission of light from oxygen atoms in the thermosphere. The excitation of the ionospheric oxygen that produces SAR arcs is caused, in turn, by the conduction of heat from the magnetospheric ring current. Advances in camera optics, including more sensitive sensors and highly specific filters, have allowed researchers to track the occurrence of SAR arcs, opening a window into the dynamics of the inner magnetosphere.

New Microslice Technology for Hyperspectral Imaging

We present the results of a project to develop a proof of concept for a novel hyperspectral imager based on the use of advanced micro-optics technology. The technology gives considerably more spatial elements than a classic pushbroom which translates into far more light being integrated per unit of time. This permits us to observe at higher spatial and/or spectral resolution, darker targets and under lower illumination, as in the early morning. Observations of faint glow at night should also be possible but need further studies. A full instrument for laboratory demonstration and field tests has now been built and tested. It has about 10,000 spatial elements and spectra 150 pixel long. It is made of a set of cylindrical fore-optics followed by a new innovative optical system called a microslice Integral Field Unit (IFU) which is itself followed by a standard spectrograph. The fore-optics plus microslice IFU split the field into a large number of small slit-like images that are dispersed in the spectrograph. Our goal is to build instruments with at least hundreds of thousands of spatial elements.

Jackson Hole Wildlife Park: An Experiment to Bridge Tourism and Conservation

From a vantage point on a rise above the Snake River, the valley below is shrouded in darkness. A faint glow on the eastern horizon heralds the dawn. The only sound comes from the river as water gurgles over rocks and other impediments. As the sky grows brighter, the shadows in the valley begin to take form, revealing numerous small streams that braid through dense thickets of willows and other shrubbery before returning to the main river channel. Small dark shapes dart among the trees and shrubs, filling the air with a variety of birdsongs. As the rising sun gradually illuminates the valley a herd of elk rise, one-by-one, in a distant meadow and begin grazing on the spring grasses. Moments later a cow moose and her calf emerge from behind the willows at the water’s edge, scattering the birds. This area, with its mosaic of habitats, teems with wildlife. It is not surprising, then, that this upper part of Jackson Hole became the chosen site for the Jackson Hole Wildlife Park (JHWP) and became the Park’s main animal viewing area for tourists and scientists alike.

Profile of Gary Ruvkun

Awash in the faint glow of a fluorescent lamp, a pair of serpentine nematode worms lie on a Petri plate, their see-through bodies magnified 100-fold by one of several microscopes arrayed in a darkened bay in National Academy of Sciences member Gary Ruvkun’s laboratory at Massachusetts General Hospital. While one of the worms wiggles its way around the plate, the other shows no signs of life, its midsection ruptured and its innards strewn asunder. A filter slides into place, and the worms are bathed in a dull green haze. The wiggling worm has a beacon of nerve cells in its head, the ganglia lit up by a genetic trick that has rescued the worm from death; its neighbor wears no such beacon. The worms were deprived of a tiny RNA molecule, called a microRNA, which helps shepherd them through their development. Through genetic engineering, Ruvkun’s graduate student has rescued the wiggling worm by returning its microRNA along with a gene for the green fluorescent beacon. Through such experiments aimed at unraveling the genetics of development, molecular biologist Ruvkun helped unearth a world of microRNAs—snippets of RNA that play a range of regulatory roles—in living cells. Today, microRNAs, which represent the smallest genes known to biologists, have become an intense focus of basic research, their study bearing implications for diseases such as diabetes, schizophrenia, and cancer. Gary Ruvkun. Expression of a microRNA rescued the glowing nematode ( Left ) from death ( Right ). Image courtesy of Zhen Shi (Massachusetts General Hospital, Boston, MA). Emblematic of the Sputnik era that spurred the scientific bent of many researchers, Ruvkun’s childhood interest in science began during the 1960 launch of the first US communications satellite Echo, which could be seen as it inched across the night skies over the San Francisco Bay area, where he grew up. …

The mesh disturbance effects in a low‐temperature cascade arc torch for surface modification of low density polyethylene

AbstractA stainless steel mesh was placed in a low‐temperature cascade arc torch (LTCAT) to study its disturbance effects on the plasmas and on the surface modification of low density polyethylene (LDPE). It was found that the photoemitting species were deflected by the screen and only faint glow was observed after the mesh. Optical emission spectroscopy examination indicated that the amount of electronically excited species in the plasma was greatly reduced after passing through the mesh. Grounding the mesh altered the nature of the discharge and a greater intensity of O emission was observed in Ar LTCAT + O2 discharge, which indicated greater energy transfer to the oxygen. Although a decrease in surface damage was observed on the treated LDPE samples by placement of the mesh in the Ar LTCAT discharges, the wettability achieved was also greatly reduced. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Experimental study on mode and mechanism of multi-pulse atmospheric-pressure glow discharges

Multi-pulse atmospheric-pressure glow discharges between two slightly unparallel electrodes were carried out in helium. The mode of discharge was investigated using an intensified charge-coupled device camera. The discharge current through gas gap and surface charge on the solid dielectric barrier were calculated. Based on analysis of surface charge on the solid barrier, space charges in gas gap, applied voltage across electrodes and field strength in gas gap, the formation mechanism of multi-pulse discharge was discussed. The discharge evolution pictures show that discharge is generated at the narrower side. At the other side, discharge is also generated at the first current peak. Physical process of the first pulse of atmospheric-pressure glow discharge in helium starts from a Townsend discharge leading to a glow discharge, and that of each subsequent current pulse is a glow discharge. Between two consecutive current pulses, a faint glow discharge is maintained in the gas gap. Theoretical analysis shows that multi-pulse discharge is a result of co-evolution of both surface charge as well as space charge and applied voltage, and the Townsend discharge does not appear during current pulse sequence of the same half cycle, except for discharge inception.