Trapped nonneutral plasmas, liquids, and crystals (the thermal equilibrium states)

Dubin, D. H. E.; O’Neil, T. M.

doi:10.1103/revmodphys.71.87

Cited by 724 publications

(827 citation statements)

References 153 publications

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“…In accurate mass measurements using ion traps single ions of different m/z are introduced into the cell consecutively. Even these precautions are not enough to avoid fully the ion-ion interaction problem since ion-image charge interaction still exists and causes the diocotron a motion 18 thus disturbing cyclotron motion frequency. This effect introduces mass errors of the order of 10 À8 to 10 À9 crucial to absolute mass measurements.…”

mentioning

confidence: 99%

Realistic modeling of ion cloud motion in a Fourier transform ion cyclotron resonance cell by use of a particle‐in‐cell approach

Nikolaev

Heeren

Popov

et al. 2007

Rapid Comm Mass Spectrometry

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Using a 'Particle-In-Cell' approach taken from plasma physics we have developed a new threedimensional (3D) parallel computer code that today yields the highest possible accuracy of ion trajectory calculations in electromagnetic fields. This approach incorporates coulombic ion-ion and ion-image charge interactions into the calculation. The accuracy is achieved through the implementation of an improved algorithm (the so-called Boris algorithm) that mathematically eliminates cyclotron motion in a magnetic field from digital equations for ion motion dynamics. It facilitates the calculation of the cyclotron motion without numerical errors. At every time-step in the simulation the electric potential inside the cell is calculated by direct solution of Poisson's equation. Calculations are performed on a computational grid with up to 128 T 128 T 128 nodes using a fast Fourier transform algorithm. The ion populations in these simulations ranged from 1000 up to 1 000 000 ions. A maximum of 3 000 000 time-steps were employed in the ion trajectory calculations. This corresponds to an experimental detection time-scale of seconds. In addition to the ion trajectories integral time-domain signals and mass spectra were calculated. The phenomena observed include phase locking of particular m/z ions (high-resolution regime) inside larger ion clouds. A focus was placed on behavior of a cloud of ions of a single m/z value to understand the nature of Fourier transform ion cyclotron resonance (FTICR) resolution and mass accuracy in selected ion mode detection. The behavior of two and three ion clouds of different but close m/z was investigated as well. Peak coalescence effects were observed in both cases. Very complicated ion cloud dynamics in the case of three ion clouds was demonstrated. It was found that magnetic field does not influence phase locking for a cloud of ions of a single m/z. The ion cloud evolution time-scale is inversely proportional to magnetic field. The number of ions needed for peak coalescence depends quadratically on the magnetic field. Copyright # 2007 John Wiley & Sons, Ltd.The leading role Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) plays in biological mass spectrometry is directly related to its unsurpassed resolution and mass accuracy combined with the possibility of utilizing all known ionization and fragmentation methods. Further improvement of mass accuracy will be greatly facilitated by a more detailed understanding of the motion of ions during ion introduction into the FTICR cell, excitation of their cyclotron motion, fragmentation and detection of induced signal. Starting from the early days of FTICR-MS the theory of ion motion in the ICR cell was an important research topic in this field. The dynamics of single particles inside the FTICR trap was analyzed by many groups in both the FTICR and physics communities. [1][2][3][4][5][6][7][8] The FTICR community has been interested mainly in obtaining a calibration formula, which connects measured frequency with ion mass. 9 The e...

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mentioning

confidence: 99%

Realistic modeling of ion cloud motion in a Fourier transform ion cyclotron resonance cell by use of a particle‐in‐cell approach

Nikolaev

Heeren

Popov

et al. 2007

Rapid Comm Mass Spectrometry

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“…The exact solutions can also be useful as bench tests for novel analytical and numerical methods for solving nonlinear partial differential equations [1,2] and as a guide for numerical study of more complex and realistic problems [5,8].…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, there also exists a number of nonperturbative plasma wave solutions of relatively simple problems, (see, e.g., [3][4][5][6][7][8][9][10][11]). Besides useful for understanding quasi-steady dynamic states and fully nonlinear evolution of waves and instabilities, such exact solutions are also important for verifying new analytical and numerical methods for solving nonlinear partial differential equations, as well as in formulating more realistic problems [4,5]. Recently, an exact model for cold plasma motion is used to investigate the energy transfer among the different degrees of freedom in a rotating plasma [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Energy coupling among the degrees of freedom in an electron–positron plasma

Zhang

Karimov

et al. 2010

J. Plasma Phys.

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Abstract. Nonlinear coupling of the motion in the three spatial degrees of freedom of a cold fluid electron-positron plasma is investigated. Exact solutions describing expanding flows with oscillations are obtained. It is found that the energy in the irrotational flow component is in general transferred to the rotational components, but not in the reversed direction. Furthermore, since the density evolution need not be related to all the three flow components, oscillations in one or two of the flow fields can be purely electromagnetic and are not accompanied by density oscillations.

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“…Fortunately, excellent radial confinement of nonneutral plasmas in a strong axial magnetic field follows from angular momentum conservation. Summarizing Dubin and O'Neil [93,94], the total canonical angular momentum, P θ , for N charged particles can be written (in cylindrical coordinates) as, 25) where v θj is the angular velocity, r j is the distance from the axis of symmetry (or radius)…”

Section: Confinement Of Charged Plasmasmentioning

confidence: 99%

Detection of Trapped Antihydrogen

Hydomako

2013

Springer Theses

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The ALPHA experiment is an international effort to produce, trap, and perform precision spectroscopic measurements on antihydrogen (the bound state of a positron and an antiproton). Based at the Antiproton Decelerator (AD) facility at CERN, the ALPHA experiment has recently magnetically confined antihydrogen atoms for the first time. A crucial element in the observation of trapped antihydrogen is ALPHA's silicon vertexing detector. This detector contains sixty silicon modules arranged in three concentric layers, and is able to determine the three-dimensional location of the annihilation of an antihydrogen atom by reconstructing the trajectories of the produced annihilation products.This dissertation focuses mainly on the methods used to reconstruct the annihilation location. Specifically, the software algorithms used to identify and extrapolate charged particle tracks are presented along with the routines used to estimate the annihilation location from the convergence of the identified tracks. It is shown that these methods can determine the annihilation location with a spatial resolution between about 0.6 to 0.8 cm (depending on the coordinate being measured). Furthermore, a robust analysis to identify and reduce cosmic ray background events is described. The cosmic ray background can obscure the trapped antihydrogen signal, and its suppression leads to a significant increase in the annihilation detection sensitivity. The background suppression analysis involves examining the reconstructed detector event based on several selection criteria, including: the number of charged particle tracks, the radial vertex position, and a fit of a straight line to the event hit positions. By carefully optimizing these criteria, (99.54 ± 0.02)% of cosmic ray events are rejected, while (64.4 ± 0.1)% of antihydrogen annihilation events are retained. Finally, the experimental results demonstrating the first-ever magnetic confinement of antihydrogen atoms are presented. These results rely heavily on the silicon i detector, and as such, the role of the annihilation vertex reconstruction is emphasized.

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Trapped nonneutral plasmas, liquids, and crystals (the thermal equilibrium states)

Cited by 724 publications

References 153 publications

Realistic modeling of ion cloud motion in a Fourier transform ion cyclotron resonance cell by use of a particle‐in‐cell approach

Realistic modeling of ion cloud motion in a Fourier transform ion cyclotron resonance cell by use of a particle‐in‐cell approach

Energy coupling among the degrees of freedom in an electron–positron plasma

Detection of Trapped Antihydrogen

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