scholarly journals Outflow of low-energy O<sup>+</sup> ion beams observed during periods without substorms

2015 ◽  
Vol 33 (3) ◽  
pp. 333-344 ◽  
Author(s):  
G. K. Parks ◽  
E. Lee ◽  
S. Y. Fu ◽  
M. Fillingim ◽  
I. Dandouras ◽  
...  
Keyword(s):  
Flow Rate ◽  
Heavy Ion ◽  
Auroral Oval ◽  
Ion Beams ◽  
Low Energy ◽  
Ion Composition ◽  
Spacecraft Potential ◽  
Imaging Camera ◽  
Cluster Ion ◽  
Low Energy Ions

Abstract. Numerous observations have shown that ions flow out of the ionosphere during substorms with more fluxes leaving as the substorm intensity increases (Wilson et al., 2004). In this article we show observations of low-energy (few tens of electron volts) ionospheric ions flowing out periods without substorms, determined using the Wideband Imaging Camera (WIC) and Auroral Electrojet (AE) indices. We use Cluster ion composition data and show the outflowing ions are field-aligned H+, He+ and O+ beams accelerated to energies of ~40–80 eV, after correcting for spacecraft potential. The estimated fluxes of the low-energy O+ ions measured at ~20 000 km altitude are >103–105 cm−2 s. Assuming the auroral oval is the source of the escaping ions, the measured fluxes correspond to a flow rate of ~1019–1021 ions s−1 leaving the ionosphere. However, periods without substorms can persist for hours suggesting the low-energy ions flowing out during these times could be a major source of the heavy ion population in the plasma sheet and lobe.

THE ENERGY LOSS, THE DETERIORATION DEPTH, AND THE LIGHT OUTPUT FOR HEAVY IONS IN ZnO:Zn

1967 ◽  
Vol 45 (12) ◽  
pp. 4039-4051 ◽  
Author(s):  
L. Hastings ◽  
A. van Wijngaarden
Keyword(s):  
Energy Loss ◽  
Heavy Ions ◽  
Light Output ◽  
Average Energy ◽  
Ion Beams ◽  
Low Energy ◽  
Energy Losses ◽  
Sufficient Energy ◽  
Low Energy Ions ◽  
Total Average

Local regions on the surface of ZnO:Zn phosphor samples were deteriorated by a large number of low-energy ions. In this manner thin films which did not luminesce under ion bombardment were prepared. The phosphor samples were then scanned across energetic ion beams with sufficient energy to traverse the thin phosphor films. By comparing the luminescent response to this ion excitation in the damaged and undamaged portions of the phosphor surface, the total average energy losses of 1H, 4He, 14N, 40Ar, and 84Kr in passing through the films were determined. It was found that the energy losses for the heavier projectiles, when compared with the energy loss of hydrogen, are appreciably smaller than the energy losses predicted by the Lindhard and Scharff theory.The deterioration depth of the phosphor under prolonged bombardment is proportional to the speed of the damaging projectiles.

The Spacecraft Potential’s Influence on the FOV of Rosetta-ICA at Low Ion Energies

2020 ◽  
Author(s):  
Sofia Bergman ◽  
Gabriella Stenberg Wieser ◽  
Martin Wieser ◽  
Fredrik Johansson ◽  
Anders Eriksson
Keyword(s):  
Debye Length ◽  
Low Energy ◽  
In Situ Techniques ◽  
Positive Ions ◽  
Spacecraft Potential ◽  
Energy Part ◽  
Ion Energies ◽  
Low Energies ◽  
Composition Analyzer ◽  
Low Energy Ions

&lt;p&gt;&lt;span&gt;Low-energy ions play important roles in many processes in the environments around various bodies in the solar system. At comets, they are, for example, important for the understanding of the interaction of the cometary particles with the solar wind, including the formation of the diamagnetic cavity. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;Unfortunately, spacecraft charging makes low-energy ions difficult to measure using in-situ techniques. The charged spacecraft surface will attract or repel the ions prior to detection, affecting both their trajectories and energy. The affected trajectories will change the effective FOV of the instrument. A negatively charged spacecraft will focus incoming positive ions, enlarging and distorting the FOV.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;We model the low-energy FOV distortion of the Ion Composition Analyzer (ICA) on board Rosetta. ICA is an ion spectrometer measuring positive ions with an energy range of a few eV to 40 keV. Rosetta was commonly charged to a negative potential throughout the mission, and consequently the positive ions were accelerated towards the spacecraft before detection. This distorted the low-energy part of the data. We use the Spacecraft Plasma Interaction Software (SPIS) to simulate the environment around the spacecraft and backtrace particles from the instrument. We then compare the travel direction of the ions at detection and infinity, and draw conclusions about the resulting FOV distortion. We investigate the distortion for different spacecraft potentials and Debye lengths of the surrounding plasma. &lt;/span&gt;&lt;/p&gt;&lt;p&gt; &lt;span&gt;The results show that the effective FOV of ICA is severely distorted at low energies, but the distortion varies between different viewing directions of the instrument. It is furthermore sensitive to changes in the Debye length and we observe a small non-linearity in the relation between FOV distortion, ion energy and spacecraft potential. Generally, the FOV is not significantly affected when the energy of the ions is above twice the spacecraft potential. &lt;/span&gt;&lt;/p&gt;

SUPER SEPARATOR SPECTROMETER FOR THE LINAG HEAVY ION BEAMS

2009 ◽  
Vol 18 (10) ◽  
pp. 2160-2168 ◽  
Author(s):  
A. DROUART ◽  
J. A. NOLEN ◽  
H. SAVAJOLS
Keyword(s):  
Electron Spectroscopy ◽  
Heavy Ion ◽  
High Energy ◽  
Ion Beams ◽  
Low Energy ◽  
Current Status ◽  
Secondary Reactions ◽  
Two Stages ◽  
Rotating Target ◽  
Very High

The Super Separator Spectrometer (S3) will receive the very high intensity heavy ion beams from the LINAG accelerator of SPIRAL2. Its privileged fields of physics are the delayed study of rare nuclei and secondary reactions with exotic nuclei. The project is presently in a phase of conceptual design. It includes a rotating target to sustain the high energy deposit, a two stages separator (momentum achromat) and spectrometer (mass spectrometer). Various detection set-ups are foreseen, especially a delayed α, γ, and electron spectroscopy array and a gas catcher coupled to a low energy branch. We present here the current status of the project and its main features.

Gas Cluster Ion Beam Technology for Nano-Fabrication

2012 ◽  
Vol 82 ◽  
pp. 1-8
Author(s):  
Noriaki Toyoda ◽  
Isao Yamada
Keyword(s):  
Ion Beam ◽  
Surface Region ◽  
Local Area ◽  
Industrial Applications ◽  
Ion Beams ◽  
Low Energy ◽  
Cluster Ions ◽  
Nano Fabrication ◽  
Cluster Ion ◽  
Gas Cluster Ion Beam

A gas cluster is an aggregate of a few to several thousands of gaseous atoms or molecules, and it can be accelerated to a desired energy after ionization. Since the kinetic energy of an atom in a cluster is equal to the total energy divided by the cluster size, a quite-low-energy ion beam can be realized. Although it is difficult to obtain low-energy monomer ion beams due to the space charge effect, equivalently low-energy ion beams can be realized by using cluster ion beams at relatively high acceleration voltages. Not only the low-energy feature but also the dense energy depositions at a local area are important characteristics of the irradiation by gas cluster ions. All of the impinging energy of a gas cluster ion is deposited at the surface region, and this dense energy deposition is the origin of enhanced sputtering yields, crater formation, shockwave generation, and other non-linear effects. GCIBs are being used for industrial applications where a nano-fabrication process is required. Surface smoothing, shallow doping, low-damage etching, trimming, and thin-film formations are promising applications of GCIBs. In this paper, fundamental irradiation effects of GCIB are discussed from the viewpoint of low-energy irradiation, sputtering, and dense energy depositions. Also, various applications of GCIB for nano-fabrications are explained.

scholarly journals Flow directions of low-energy ions in and around the diamagnetic cavity of comet 67P

2021 ◽  
Author(s):  
Sofia Bergman ◽  
Gabriella Stenberg Wieser ◽  
Martin Wieser ◽  
Hans Nilsson ◽  
Erik Vigren ◽  
...  
Keyword(s):  
Flow Direction ◽  
Low Energy ◽  
Expansion Velocity ◽  
Directional Information ◽  
Particle In Cell ◽  
Spacecraft Potential ◽  
Cell Simulation ◽  
Flow Directions ◽  
Low Energy Ions ◽  
Comet 67P

Abstract The flow direction of low-energy ions around comet 67P/Churyumov-Gerasimenko has previously been difficult to constrain due to the influence of the spacecraft potential. The Ion Composition Analyzer of the Rosetta Plasma Consortium (RPC-ICA) on Rosetta measured the distribution function of positive ions with energies down to just a few eV/q throughout the escort phase of the mission. Unfortunately, the substantial negative spacecraft potential distorted the directional information of the low-energy data. In this work, we present the flow directions of low-energy ions around comet 67P, corrected for the spacecraft potential using Particle-In-Cell simulation results. We focus on the region in and around the diamagnetic cavity, where low-energy ions are especially important for the dynamics. We separate between slightly accelerated “burst” features and a more constant “band” of low-energy ions visible in the data. The “bursts” are flowing radially outwards from the nucleus with an anti-sunward component while the “band” is predominantly streaming back towards the comet. This provides evidence of counter-streaming ions, which has implications for the overall expansion velocity of the ions. The backstreaming ions are present also at times when the diamagnetic cavity was not detected, indicating that the process accelerating the ions back towards the comet is not connected to the cavity boundary.

Response of CR-39 track detector to low-energy heavy ion beams

2008 ◽  
Vol 43 ◽  
pp. S79-S81 ◽  
Author(s):  
Ippei Ishikawa ◽  
Atsuya Kishi ◽  
Wataru Kada ◽  
Fuminobu Sato ◽  
Yushi Kato ◽  
...  
Keyword(s):  
Heavy Ion ◽  
Track Detector ◽  
Ion Beams ◽  
Low Energy

The relevance of very low energy ions for heavy-ion therapy

2009 ◽  
Vol 54 (7) ◽  
pp. N101-N106 ◽  
Author(s):  
T Elsässer ◽  
A Gemmel ◽  
M Scholz ◽  
D Schardt ◽  
M Krämer
Keyword(s):  
Heavy Ion ◽  
Low Energy ◽  
Heavy Ion Therapy ◽  
Ion Therapy ◽  
Low Energy Ions

Observations of low energy ions around the diamagnetic cavity at comet 67P

2020 ◽  
Author(s):  
Gabriella Stenberg Wieser ◽  
Martin Wieser ◽  
Sofia Bergman ◽  
Elias Odelstad ◽  
Fredrik Johansson ◽  
...  
Keyword(s):  
Ion Flux ◽  
Low Energy ◽  
Electron Velocity ◽  
Ion Dynamics ◽  
Ion Temperature ◽  
Electron Velocity Distribution ◽  
Spacecraft Potential ◽  
Sudden Decrease ◽  
Low Energy Ions ◽  
Comet 67P

&lt;p&gt;We investigate the variations in low energy cometary ions around comet 67P. Detailed measurements of these ions were made possible by implementing a new instrumental mode of the ion mass spectrometer on the Rosetta spacecraft. The nominal time resolution was increased from 192 s to 4 s at the expense of the energy range and the field-of-view.&lt;/p&gt;&lt;p&gt;In this study we focus on ion observations made outside of, but in the vicinity of, the diamagnetic cavity. The ion dynamics here is clearly linked to variations of the magnetic field strength and properties of the electron velocity distribution, manifested by the spacecraft potential. Preliminary results show that the ion flux correlates with the changes of the spacecraft potential. The maximum ion flux is, however, observed about 20 seconds after a sudden decrease of the potential (corresponding to an increase in electron density if electron temperature is constant). We also find evidence of small ion temperature increases both when the spacecraft potential changes fast and at the time of maximum ion flux.&lt;/p&gt;

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