EXOTIC MOLECULAR IONS (HeH)2+ AND ${\rm He}_2^{3+}$ IN A STRONG MAGNETIC FIELD: LOW-LYING STATES

2007 ◽  
Vol 22 (08n09) ◽  
pp. 1605-1626 ◽  
Author(s):  
A. V. TURBINER ◽  
J. C. LÓPEZ VIEYRA
Keyword(s):  
Magnetic Field ◽  
Molecular Ions ◽  
Final State ◽  
Nonrelativistic Approximation ◽  
Internuclear Axis ◽  
Vibrational Energies ◽  
Parallel Configuration ◽  
The Magnetic Field ◽  
Coulombic Systems ◽  
Α Particles

The Coulombic systems (αpe) and (ααe), (αppe), (ααpe) and ( Li 3+ Li 3+e) placed in a magnetic field B ≳ 1011 G are studied. It is demonstrated a theoretical existence of the exotic ion ( He H )2+ for B ≳ 5 × 1012 G in parallel configuration (the magnetic field is directed along internuclear axis) as optimal as well as its excited states 1π, 1δ. As for the exotic ion [Formula: see text] it is shown that in spite of strong electrostatic repulsion of α-particles this ion can also exist for B ≳ 100 a.u. (= 2.35 × 1011 G ) in parallel configuration as optimal in the states 1σg (ground state), 1πu, 1δg. Upon appearance both ions are unstable towards dissociation with He + in the final state but with very large lifetime. However, at B ≳ 10000 a.u. , the ion ( He H )2+ becomes stable, while at B ≳ 1000 a.u. , the ion [Formula: see text] becomes stable. For both ions the vibrational and rotational energies are calculated. With a magnetic field growth, both exotic ions become more and more tightly bound and compact, their lowest rotational and vibrational energies grow drastically. At the edge of applicability of nonrelativistic approximation, B ~ 4.414 × 1013 G , there are indications that three more exotic linear ions ( H – He – H )3+, ( He – H – He )4+ and even [Formula: see text] in parallel configuration may also occur.

COULOMB SYSTEMS IN A STRONG MAGNETIC FIELD

2005 ◽  
Vol 20 (37) ◽  
pp. 2845-2854 ◽  
Author(s):  
A. V. TURBINER ◽  
J. C. LÓPEZ-VIEYRA
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Coulomb Systems ◽  
Electron Systems ◽  
Molecular Physics ◽  
Weakly Bound ◽  
Molecular Systems ◽  
Internuclear Axis ◽  
Parallel Configuration ◽  
Coulombic Systems

A study of what would the atomic–molecular physics be in an external strong magnetic field is presented. Emphasis is made on one-electron systems which seem the most bound, since two- and more-electron systems are weakly bound due to their maximal total spin nature. We demonstrate that the Coulombic systems (αpe) and (ααe) placed in (astro-physically relevant) magnetic fields B>1011 G become bound. It manifests a theoretical existence of the exotic ions ( HeH )2+ and [Formula: see text] with parallel configuration (the magnetic field is directed along the internuclear axis) as optimal. Both ions are unstable towards dissociation but do have very large lifetimes. At B>1000 a.u. the ion [Formula: see text] becomes stable and even becomes the most stable among one-electron ions made from protons and/or α-particles. A table of one-electron atomic–molecular systems which may exist in a strong magnetic field is given.

scholarly journals Energy Correlations of α-Particles in the 8Be-Nucleus Ground-State Formation Channel of the 12C(γ,3α) and 16O(γ,4α) Reactions

2019 ◽  
Vol 64 (9) ◽  
pp. 787
Author(s):  
S. N. Afanasyev
Keyword(s):  
Magnetic Field ◽  
Photon Energy ◽  
Relative Motion ◽  
Cross Sections ◽  
Ground State ◽  
Diffusion Chamber ◽  
Mechanism Of Interaction ◽  
The Magnetic Field ◽  
Maximum Photon ◽  
Α Particles

The method of diffusion chamber in the magnetic field making use of a bremsstrahlung beam with a maximum photon energy of 150 MeV is applied to study the 12C(y,3a) and 16O(y,4a) reactions. A resonance identified as the ground state of 8Be nucleus is found in the distribution of events over the energy of the relative motion of two a-particles. The partial cross-sections of the 8Be nucleus formation channels are measured. It is shown that the mechanism of interaction between a y-quantum and a virtual a-particle pair takes place in this case.

scholarly journals Extensional Magnetorheology as a Tool for Optimizing the Formulation of Ferrofluids in Oil-Spill Clean-Up Processes

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 597 ◽  
Author(s):  
José Hermenegildo García-Ortiz ◽  
Francisco José Galindo-Rosales
Keyword(s):  
Magnetic Field ◽  
Oil Spill ◽  
Particle Concentration ◽  
Flow Direction ◽  
Extensional Flow ◽  
Rheological Behaviour ◽  
Magnetic Saturation ◽  
Parallel Configuration ◽  
Thinning Process ◽  
The Magnetic Field

In this study, we propose a new way of optimising the formulation of ferrofluids for oil-spill clean-up processes, based on the rheological behaviour under extensional flow and magnetic fields. Different commercial ferrofluids (FFs), consisting of a set of six ferrofluids with different magnetic saturation and particle concentration, were characterised in a Capillary Break-Up Extensional Rheometer (CaBER) equipped with two magnetorheological cells that allow imposing a homogeneous and tunable magnetic field either parallel or perpendicular to the flow direction. The filament thinning process with different intensities and orientation of the magnetic field with respect to the flow direction was analysed, and the results showed that the perpendicular configuration did not have a significant effect on the behaviour of the ferrofluids, as in shear magnetorheometry. However, the parallel configuration allowed to determine that the formulation of ferrofluids for oil-spill cleaning processes should consist of a 4% vol concentration of magnetic nanoparticles with a magnetic saturation of M s > 20 mT.

scholarly journals An automatic magnetic field stabilizer of high sensitivity

1934 ◽  
Vol 145 (854) ◽  
pp. 250-257 ◽  
Keyword(s):  
Magnetic Field ◽  
High Sensitivity ◽  
Battery Voltage ◽  
Cavendish Laboratory ◽  
Counting Chamber ◽  
Coil Resistance ◽  
Magnet Coil ◽  
The Magnetic Field ◽  
A Current ◽  
Α Particles

The present paper describes a method whereby the field of an electromagnet can be kept constant automatically to at least one part in fifty thousand ( i. e. , to 0⋅2 gauss in 10,000 gauss) for long periods. The method has the great advantage of not merely ensuring that the current through the magnet (or, say, the voltage across the magnet windings) is kept constant, but that the field itself , as measured by a fluxmeter, is kept within one-fifth of a gauss (or less) of some desired value. Thus, it is not necessary to know whether a fluctuation of the field is caused by unsteadiness of the exciting battery voltage, variations of the magnet coil resistance with temperature, etc. ; in all cases, the stabilizer automatically readjusts the exciting current until the field is brought back to its original value. Further, as explained at the end of the paper, the stabilizer can be made to bring about an increase or decrease in the field of a definite number of gauss, and to continue to maintain the field at this new value. Also with very slight modifications, which are so obvious as to require no further explanation, the stabilizer could be made to maintain a current, or a potential difference, constant just as easily as a magnetic field. The method has been applied with success to the annular magnetic field used in the Cavendish Laboratory. The magnet is used for the analysis of α-particle groups. Under the influence of suitable fields of the order of 10,000 gauss, α-particles of various velocities are made to travel in a semicircle of 40 cm. radius, and are focussed on to the slit of a counting chamber. Groups of various velocities are focussed in turn by varying the field, their velocities being determined from the values of the fields. It is extremely important, therefore, to know the field strength with accuracy and to maintain it constant, at each of these values, during the experiment. In some experiments already described this was done manually. An observer watched the spot of light reflected from the mirror of a fluxmeter, the coil of which was connected to a stationary search coil situated in the magnetic field. A change of one-fifth of a gauss in the magnetic field produced a deflection of the fluxmeter spot of about 1 mm., and by suitable adjustment of the field current by means of a mercury rheostat it could be arranged that the spot was kept within half a millimetre of its zero portion. This, however, required one observer to spend his whole time in stabilizing the field during an experiment which might last several hours.

scholarly journals Mirror mode physics: Amplitude limit

2019 ◽  
Author(s):  
Rudolf A. Treumann ◽  
Wolfgang Baumjohann
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Dominant Role ◽  
Sound Waves ◽  
Final State ◽  
Temperature Plasma ◽  
Electron Pairs ◽  
Mirror Mode ◽  
Spacecraft Data ◽  
The Magnetic Field

Abstract. The mirror mode evolving in collisionless magnetised high-temperature thermally anisotropic plasmas is shown to resemble a macro-quantum state. Starting as a classical zero frequency ion fluid instability it saturates quasi-linearly at very low magnetic level, while forming extended magnetic bubbles.It traps the electron component into an adiabatic bounce motion along the magnetic field which causes a bulk electron anisotropy. This can drive an electron mirror mode (see Treumann and Baumjohann, 2018b, who identified it in old spacecraft data). More important, however, we show that trapped electrons play the dominant role of further evolution towards a stationary state. Interaction of the trapped bouncing electrons with the thermal level of ion sound waves causes attractive potentials between electrons and forms electron pairs in the lowest-energy singlet state of two combined electrons. This happens preferentially near the electron mirror points resulting in a diamagnetic current effect which ultimately drives evolution of the magnetic field into large amplitude mirror bubbles causing diamagnetism and expelling a larger fraction of magnetic flux from the interior of the initial quasi-linearly stable mirror mode bottle. Estimates given in view of mirror modes in the magnetosheath are in reasonable numerical agreement with observation. We derive the self-consistent final state of the mirror bubbles. This analysis demonstrates that the observed mirror mode in high temperature space plasmas (solar wind, magnetosheath, magnetotail) is not a simple magnetohydrodynamic instability. It resembles a classical super-conducting, super-fluid state in high temperature plasma under conditions when electron pairs form. This is a most interesting observation which suggests that pair formation can become relevant in space and astrophysics.

scholarly journals Collisional polarization of molecular ions: a signpost of ambipolar diffusion

2020 ◽  
Vol 638 ◽  
pp. L7
Author(s):  
Boy Lankhaar ◽  
Wouter Vlemmings
Keyword(s):  
Magnetic Field ◽  
Classical Model ◽  
Critical Density ◽  
Molecular Ions ◽  
Ambipolar Diffusion ◽  
Neutral Medium ◽  
Magnetic Field Direction ◽  
Collision Partner ◽  
Velocity Drift ◽  
The Magnetic Field

Magnetic fields play a role in the dynamics of many astrophysical processes, but they are hard to detect. In a partially ionized plasma, a magnetic field works directly on the ionized medium but not on the neutral medium, which gives rise to a velocity drift between them: ambipolar diffusion. This process is suggested to be important in the process of star formation, but has never been directly observed. We introduce a method that could be used to detect ambipolar diffusion and the magnetic field that gives rise to it, where we exploit the velocity drift between the charged and neutral medium. By using a representative classical model of the collision dynamics, we show that molecular ions partially align themselves when a velocity drift is present between the molecular ion and its main collision partner H2. We demonstrate that ambipolar diffusion potently aligns molecular ions in regions denser than their critical density. We include a model for HCO+ and show that collisional polarization could be detectable for the ambipolar drifts predicted by numerical simulations of the inner protostellar disk regions. The polarization vectors are aligned perpendicular to the magnetic field direction projected on the plane of the sky.

scholarly journals Why is the H 3 + hot spot above Jupiter's Great Red Spot so hot?

2019 ◽  
Vol 377 (2154) ◽  
pp. 20180407 ◽  
Author(s):  
L. C. Ray ◽  
C. T. S. Lorch ◽  
J. O'Donoghue ◽  
J. N. Yates ◽  
S. V. Badman ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Gravity Waves ◽  
Inclination Angle ◽  
Joule Heating ◽  
Acoustic Waves ◽  
Lower Stratosphere ◽  
Hot Spot ◽  
Molecular Ions ◽  
Atmospheric Gravity ◽  
The Magnetic Field

Recent observations of Jupiter's Great Red Spot indicate that the thermosphere above the storm is hotter than its surroundings by more than 700 K. Possible suggested sources for this heating have thus far included atmospheric gravity waves and lightning-driven acoustic waves. Here, we propose that Joule heating, driven by Great Red Spot vorticity penetrating up into the lower stratosphere and coupling to the thermosphere, may contribute to the large observed temperatures. The strength of Joule heating will depend on the local inclination angle of the magnetic field and thus the observed emissions and inferred temperatures should vary with planetary longitude as the Great Red Spot tracks across the planet. This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond’.

Observing the galactic magnetic field

1967 ◽  
Vol 31 ◽  
pp. 375-380
Author(s):  
H. C. van de Hulst
Keyword(s):  
Magnetic Field ◽  
Fair Agreement ◽  
Solar Neighbourhood ◽  
Galactic Magnetic Field ◽  
The Magnetic Field

Various methods of observing the galactic magnetic field are reviewed, and their results summarized. There is fair agreement about the direction of the magnetic field in the solar neighbourhood:l= 50° to 80°; the strength of the field in the disk is of the order of 10-5gauss.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

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