scholarly journals Low Frequency Emission Regions in Pulsars

2002 ◽  
Vol 199 ◽  
pp. 377-378
Author(s):  
Jaroslaw Kijak
Keyword(s):  
Neutron Star ◽  
Low Frequency ◽  
Component Separation ◽  
Geometrical Method ◽  
Polar Cap ◽  
Pulsar Emission ◽  
Different Altitudes ◽  
Frequency Radiation ◽  
Frequency Emission

The systematic increase of component separation and profile widths with decreasing frequency in pulsars suggests that the radiation at different frequencies is emitted from different altitudes above the polar cap. This concept is known as the radius-to-frequency mapping. According to RFM the observed low-frequency radiation should be generated farther from the neutron star than higher-frequency radiation. We discuss radial locations of the pulsar emission regions using a geometrical method for the estimation of emission altitudes. It is argued that the emission altitude at a given frequency is slightly different for young and old pulsars.

scholarly journals Radius-to-Frequency Mapping in the Radio Pulsar Emission Mechanism

1992 ◽  
Vol 128 ◽  
pp. 143-146
Author(s):  
S. E. Thorsett
Keyword(s):  
General Feature ◽  
Low Frequency ◽  
Radio Pulsar ◽  
Emission Mechanism ◽  
Polar Cap ◽  
Pulsar Emission ◽  
Pulsar Timing ◽  
Average Profile ◽  
Different Altitudes

AbstractA general feature of many models of the pulsar emission mechanism is that radiation of different frequencies is produced at different altitudes above the polar cap. The broadening of pulse components and increasing separation between components at low frequency is in general agreement with these theories. We review the available average profile and pulsar timing observations and discuss the implications for theories of radius-to-frequency mapping.

THE ENERGY EFFICIENCY TECHNIQUE OF THERMAL PROCESSING OF GRAIN

2019 ◽  
pp. 176-182
Author(s):  
А. Zykov ◽  
S. Orlova ◽  
L. Ovsiannykova
Keyword(s):  
Energy Efficiency ◽  
Thermal Processing ◽  
Microwave Field ◽  
Low Frequency ◽  
Heat Pipes ◽  
Biologically Active ◽  
Microwave Drying ◽  
Post Harvest ◽  
Combined Action ◽  
Frequency Radiation

The methods of energy efficiency increasing of pre- and post-harvest thermal processing of grain are considered. The effective ways to deliver energy to the grain using heat pipes and microwave field are given. The effect of combined action of microwave and low-frequency radiation on the grain germination is shown. Currently, the intensification of technological processes under the influence of microwave radiation is used in many industrial processes. Microwave equipment is becoming a necessary technological component of large profitable industries. The process of drying is no exception. In recent years, new versions of dryers have been proposed that use combined methods of energy supply, including microwave energy. Microwave dryers for foodstuffs, grains and oilseeds, including those for seed stock, have been created and are beginning to be used, along with drying and disinfection, disinfection of drying products from harmful bacteria, fungi, and mildew. For the implementation of microwave drying of particular importance is the choice of regime parameters of drying, given the fact that the grain is a biologically active object. Microwave drying allows you to provide a powerful flow of energy to the object of drying and to obtain a significant intensification of moisture evaporation. But at the same time there is also an intense heating of the product, which can degrade its quality. The possibility of supplying energy throughout the cross section of the product allows for the evaporation of moisture from the inner layers of the product, which is especially important at the end of drying, when the zone of evaporation of moisture is significantly deeper. Therefore, the highest drying efficiency can be obtained in combined processes that take advantage of various drying methods, such as convective, as well as the use of microwave and low-frequency magnetic fields. The paper presents effective ways to supply energy to the grain using heat pipes and a microwave field. The effect of the combined action of microwave and low-frequency radiation on grain similarity is shown. Ways to improve the energy efficiency of the processes of preseeding and post-harvest heat treatment of grain are considered.

scholarly journals An Emission Line in the Hard X-Ray Spectrum of Hercules X-1: Quantized Cyclotron Emission from the Neutron Star

1977 ◽  
Vol 43 ◽  
pp. 34-34
Author(s):  
W. Pietsch ◽  
C. Reppin ◽  
R. Staubert ◽  
J. Truemper ◽  
W. Voges ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Second Harmonic ◽  
Narrow Line ◽  
Electron Cyclotron Emission ◽  
Polar Cap ◽  
Astrophysical Application ◽  
X Ray ◽  
Cyclotron Emission

A four hour balloon observation of HERC X-l during the 'On-state' in the 35 day cycle was performed on May 3rd, 1976. The 1.24 second pulsations show a pulsed fraction of 58 ± 8% in the 18-31 KeV interval. A pulsed flux (1.24 sec) was discovered in the 31-88 KeV interval with a pulsed fraction of 51 ± 14%. The spectrum of the pulsed flux can be represented up to 50 KeV by an exponential distribution with KT approximately 8 KeV. At approximately 58 KeV a strong and narrow line feature occurs which we interpret as electron cyclotron emission (ΔN = 1 Landau transition) from the polar cap plasma of the rotating neutron star. The corresponding magnetic field strength is approximately 5 x 1012 Gauss, neglecting gravitational red shift. There is evidence for a second harmonic at approximately 110 KeV (ΔN = 2 ).The astrophysical application of this discovery will be discussed in some detail.

scholarly journals The nature of the low-frequency emission of M 51

2014 ◽  
Vol 568 ◽  
pp. A74 ◽  
Author(s):  
D. D. Mulcahy ◽  
A. Horneffer ◽  
R. Beck ◽  
G. Heald ◽  
A. Fletcher ◽  
...  
Keyword(s):  
Low Frequency ◽  
Frequency Emission

scholarly journals Magnetic Field due to the Radiation of High Altitude Lightning

2020 ◽  
Vol 8 (2S12) ◽  
pp. 49-50
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Radiation ◽  
High Altitude ◽  
Low Frequency ◽  
Frequency Region ◽  
Middle Region ◽  
Very Low Frequency ◽  
Lightning Discharges ◽  
Cloud To Ground Lightning ◽  
Frequency Radiation

High altitude optical discharges generated by extreme cloud-to-ground lightning strokes, which occur in the middle region of the atmosphere known as sprites. Streamer formation in sprites has been well stated to be existing by several previous workers. These streamers are not only responsible for the initiation of sprites but also they are composed of these streamers. It causes the production of electromagnetic radiation upto or below the ELF (very low frequency) region which have been reported earlier through various research theories. Thus, we are reporting out for the formulation of the model by using an earlier model used to estimate higher frequency radiation from cloud and ground lightning discharges through these positive corona streamers. Taking it into account, other terms like radiation magnetic field has been evaluated with the studied observations.

scholarly journals Neutron star QPOs from oscillating, precessing hot, thick flow

2019 ◽  
Vol 491 (3) ◽  
pp. 3245-3250
Author(s):  
P Chris Fragile
Keyword(s):  
Neutron Star ◽  
Low Frequency ◽  
Outer Radius ◽  
Horizontal Branch ◽  
X Ray ◽  
Best Fitting ◽  
Low Mass ◽  
The Moment ◽  
X Ray Binaries ◽  
Simultaneous Oscillation

ABSTRACT Across black hole (BH) and neutron star (NS) low-mass X-ray binaries (LMXBs), there appears to be some correlation between certain high- and low-frequency quasi-periodic oscillations (QPOs). In a previous paper, we showed that for BH LMXBs, this could be explained by the simultaneous oscillation and precession of a hot, thick, torus-like corona. In the current work, we extend this idea to NS LMXBs by associating the horizontal branch oscillations (HBOs) with precession and the upper-kiloHertz (ukHz) QPO with vertical epicyclic motion. For the Atoll source 4U 1608-52, the model can match many distinct, simultaneous observations of the HBO and ukHz QPO by varying the inner and outer radius of the torus, while maintaining fixed values for the mass (MNS) and spin (a*) of the NS. The best-fitting values are MNS = 1.38 ± 0.03 M⊙ and a* = 0.325 ± 0.005. By combining these constraints with the measured spin frequency, we are able to obtain an estimate for the moment of inertia of INS = 1.40 ± 0.02 × 1045 g cm2, which places constraints on the equation of state. The model is unable to fit the lower-kHz QPO, but evidence suggests that QPO may be associated with the boundary layer between the accretion flow and the NS surface, which is not treated in this work.

Braneworld effects in plasma magnetosphere of a slowly rotating magnetized neutron star

2019 ◽  
Vol 28 (10) ◽  
pp. 1950128 ◽  
Author(s):  
Javlon Rayimbaev ◽  
Bobur Turimov ◽  
Bobomurat Ahmedov
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Charge Density ◽  
Production Condition ◽  
Scalar Potential ◽  
Polar Cap ◽  
Radiation Beam ◽  
Electrical Fields ◽  
Analytical Expression ◽  
Surface Magnetic Field

Results of our previous paper [B. V. Turimov, B. J. Ahmedov and A. A. Hakimov, Phys. Rev. D 96 (2017) 104001] show that the effects of brane charges are not negligible in the magnetic field of the magnetized neutron star, in particular at the surface of the star, and increasing the value of brane tidal charges causes an increases in the value of surface magnetic field of magnetized neutron star, that is why it is important to consider the effects of braneworlds on energetic processes in the plasma magnetosphere of the neutron star. In this paper, we have obtained the analytical expression for Goldreich–Julian (GJ) charge density in braneworlds for inclined neutron star by solving Maxwell’s equations and found that the value of GJ charge density decreases in braneworlds. The analytical expression for scalar potential in the polar cap region of the neutron star has also been obtained. It is shown that the values of the parallel accelerating electrical fields increase with the increase of the value of the tidal charge near the surface of the neutron star. The influence of braneworlds on pair production condition on the surface of the neutron star and magnetospheric energy losses due to electromagnetic radiations have also been studied. We have shown how radiation beam becomes narrow due to the effects of braneworlds by studying the particle’s trajectory in the polar cap region in the [Formula: see text]–[Formula: see text] ([Formula: see text].) plane. Numerical calculations for particle motion in the polar cap region show that accelerating distance of charged particle increases up to its maximum value in braneworld in comparison with that in GR, due to additional gravitating behavior of tidal charges.

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