Zonostrophic instability driven by discrete particle noise
The consequences of discrete particle noise for a system possessing a possibly unstable collective mode are discussed. It is argued that a zonostrophic instability (of homogeneous turbulence to the formation of zonal flows) occurs just below the threshold for linear instability. The scenario provide...
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| Format: | Journal article |
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American Institute of Physics
2017
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| _version_ | 1797054827785617408 |
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| author | St-Onge, D Krommes, J |
| author_facet | St-Onge, D Krommes, J |
| author_sort | St-Onge, D |
| collection | OXFORD |
| description | The consequences of discrete particle noise for a system possessing a possibly unstable collective mode are discussed. It is argued that a zonostrophic instability (of homogeneous turbulence to the formation of zonal flows) occurs just below the threshold for linear instability. The scenario provides a new interpretation of the random forcing that is ubiquitously invoked in stochastic models such as the second-order cumulant expansion or stochastic structural instability theory; neither intrinsic turbulence nor coupling to extrinsic turbulence is required. A representative calculation of the zonostrophic neutral curve is made for a simple two-field model of toroidal ion-temperature-gradient-driven modes. To the extent that the damping of zonal flows is controlled by the ion-ion collision rate, the point of zonostrophic instability is independent of that rate. |
| first_indexed | 2024-03-06T19:02:46Z |
| format | Journal article |
| id | oxford-uuid:141c62e4-e394-4c32-a0e1-58bebf01ab3a |
| institution | University of Oxford |
| last_indexed | 2024-03-06T19:02:46Z |
| publishDate | 2017 |
| publisher | American Institute of Physics |
| record_format | dspace |
| spelling | oxford-uuid:141c62e4-e394-4c32-a0e1-58bebf01ab3a2022-03-26T10:17:41ZZonostrophic instability driven by discrete particle noiseJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:141c62e4-e394-4c32-a0e1-58bebf01ab3aSymplectic Elements at OxfordAmerican Institute of Physics2017St-Onge, DKrommes, JThe consequences of discrete particle noise for a system possessing a possibly unstable collective mode are discussed. It is argued that a zonostrophic instability (of homogeneous turbulence to the formation of zonal flows) occurs just below the threshold for linear instability. The scenario provides a new interpretation of the random forcing that is ubiquitously invoked in stochastic models such as the second-order cumulant expansion or stochastic structural instability theory; neither intrinsic turbulence nor coupling to extrinsic turbulence is required. A representative calculation of the zonostrophic neutral curve is made for a simple two-field model of toroidal ion-temperature-gradient-driven modes. To the extent that the damping of zonal flows is controlled by the ion-ion collision rate, the point of zonostrophic instability is independent of that rate. |
| spellingShingle | St-Onge, D Krommes, J Zonostrophic instability driven by discrete particle noise |
| title | Zonostrophic instability driven by discrete particle noise |
| title_full | Zonostrophic instability driven by discrete particle noise |
| title_fullStr | Zonostrophic instability driven by discrete particle noise |
| title_full_unstemmed | Zonostrophic instability driven by discrete particle noise |
| title_short | Zonostrophic instability driven by discrete particle noise |
| title_sort | zonostrophic instability driven by discrete particle noise |
| work_keys_str_mv | AT stonged zonostrophicinstabilitydrivenbydiscreteparticlenoise AT krommesj zonostrophicinstabilitydrivenbydiscreteparticlenoise |